Chapter 1

A Graphical Approach to Precalculus with Limits · 421 exercises

Problem 78

Sketch by hand the graph of the line passing through the given point and having the given slope. Label two points on the line. $$\text { Through }(-2,-3), m=-\frac{3}{4}$$

7 step solution

Problem 78

Solve each formula for the specified variable. \(S=\frac{n}{2}\left[2 a_{1}+(n-1) d\right]\) for \(a_{1} \quad\) (Mathematics)

3 step solution

Problem 79

Solve each equation and inequality analytically. Use interval notation to write the solution set for each inequality. (a) \(1-2 x=0\) (b) \(1-2 x \leq 0\) (c) \(1-2 x \geq 0\)

3 step solution

Problem 79

Sketch by hand the graph of the line passing through the given point and having the given slope. Label two points on the line. $$\text { Through }(-1,4), m=0$$

5 step solution

Problem 79

Solve each formula for the specified variable. \(s=\frac{1}{2} g t^{2}\) for \(g \quad\) (Distance traveled by a falling object)

4 step solution

Problem 79

The following table lists the U.S. total revenue generated in 2016 in billions of dollars for various companies. $$\begin{array}{l|c}\hline \text { Company } & \text { Revenue } \\\\\hline \text { Apple } & 216 \\\\\text { Alphabet } & 90 \\\\\text { Google } & 89 \\\\\text { Microsoft } & 85\end{array}$$ (a) Using ordered pairs, write a function \(A\) that gives the revenue for each company in billions of dollars. Interpret the first ordered pair. (b) Repeat part (a) using a diagram. (c) Identify the domain and range of \(A\).

4 step solution

Problem 80

Solve each equation and inequality analytically. Use interval notation to write the solution set for each inequality. (a) \(4-3 x=0\) (b) \(4-3 x \leq 0\) (c) \(4-3 x \geq 0\)

3 step solution

Problem 80

Sketch by hand the graph of the line passing through the given point and having the given slope. Label two points on the line. Through \(\left(\frac{9}{4}, 2\right),\) undefined slope

4 step solution

Problem 80

Solve each formula for the specified variable. \(A=\frac{24 f}{B(p+1)}\) for \(p \quad\) (Approximate annual interest rate)

4 step solution

Problem 81

Solve each equation and inequality analytically. Use interval notation to write the solution set for each inequality. (a) \(x+12=4 x\) (b) \(x+12>4 x\) (c) \(x+12<4 x\)

6 step solution

Problem 81

Sketch by hand the graph of the line passing through the given point and having the given slope. Label two points on the line. $$\text { Through }(0,-4), m=\frac{3}{4}$$

5 step solution

Problem 81

The function \(f\) gives the number \(y\) in thousands of radio stations on the air during year \(x .\) $$\begin{aligned}f=&\\{(1990,10.8),(2000,12.8),(2005,13.5)\\\&(2012,15.1),(2015,16.4)\\}\end{aligned}$$ (Source: M. Street Corporation.) (a) Use a mapping diagram (see HGURE 21) to represent \(f\). (b) Evaluate \(f(2000)\) and explain what it means. (c) Identify the domain and range of \(f\)

4 step solution

Problem 82

Solve each equation and inequality analytically. Use interval notation to write the solution set for each inequality. (a) \(5-3 x=x+1\) (b) \(5-3 x \leq x+1\) (c) \(5-3 x \geq x+1\)

3 step solution

Problem 82

Sketch by hand the graph of the line passing through the given point and having the given slope. Label two points on the line. $$\text { Through }(0,5), m=-2.5$$

5 step solution

Problem 82

The function \(f\) gives the number \(y\) in billions of dollars of personal health care expenditures during year \(x .\) $$\begin{array}{r}f=\\{(2010,2195),(2011,2273),(2012,2366) \\\\(2013,2436),(2014,2563),(2015,2717)\\}\end{array}$$ (Source: U.S. Center for Medicare and Medicaid Services.) (a) Use a mapping diagram to represent \(f\) (b) Evaluate \(f(2012)\) and explain what it means. (c) Identify the domain and range of \(f .\)

4 step solution

Problem 83

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(9-(x+1)<0\) (b) \(9-(x+1) \geq 0\)

6 step solution

Problem 83

Sketch by hand the graph of the line passing through the given point and having the given slope. Label two points on the line. Through \((-3,0),\) undefined slope

6 step solution

Problem 84

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(6+3(1-x) \geq 0\) (b) \(6+3(1-x)<0\)

6 step solution

Problem 85

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(2 x-3>x+2\) (b) \(2 x-3 \leq x+2\)

7 step solution

Problem 86

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(5-3 x \leq-11+x\) (b) \(5-3 x>-11+x\)

6 step solution

Problem 87

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(10 x+5-7 x \geq 8(x+2)+4\) (b) \(10 x+5-7 x<8(x+2)+4\)

11 step solution

Problem 87

By noon, 3 inches of rain had fallen during a storm. Rain continued to fall at a rate of \(\frac{1}{4}\) inch per hour. (a) Find a formula for a linear function \(f\) that models the amount of rainfall \(x\) hours past noon. (b) Find the total amount of rainfall by 2: 30 P.M.

5 step solution

Problem 88

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(6 x+2+10 x>-2(2 x+4)+10\) (b) \(6 x+2+10 x \leq-2(2 x+4)+10\)

6 step solution

Problem 88

When the relative humidity is \(100 \%\) air cools \(5.8^{\circ} \mathrm{F}\) for every 1 -mile increase in altitude. If the temperature is \(80^{\circ} \mathrm{F}\) on the ground, then \(f(x)=80-5.8 x\) calculates the air temperature \(x\) miles above the ground. Find \(f(3)\) and interpret the result. (Source: Battan, \(L\). Weather in Your Life, W.H. Freeman.)

4 step solution

Problem 89

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(x+2(-x+4)-3(x+5)<-4\) (b) \(x+2(-x+4)-3(x+5) \geq-4\)

7 step solution

Problem 89

When a bolt of lightning strikes in the distance, there is often a delay between seeing the lightning and hearing the thunder. The function \(f(x)=\frac{x}{5}\) computes the approximate distance in miles between an observer and a bolt of lightning when the delay is \(x\) seconds. (a) Find \(f(15)\) and interpret the result. (b) Graph \(y=f(x) .\) Let the domain of \(f\) be \([0,20]\).

4 step solution

Problem 89

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(5,7), Q(2,11)$$

3 step solution

Problem 90

Solve each inequality analytically, writing the solution set in interval notation. Support your answer graphically. (Hint: Once part (a) is done, the answer to part (b) follows.) (a) \(-11 x-(6 x-4)+5-3 x \leq 1\) (b) \(-11 x-(6 x-4)+5-3 x>1\)

7 step solution

Problem 90

Function \(f\) gives the median 2015 weekly income (in dollars) by educational attainment for people 25 years old and over. This function is defined by \(f(N)=493, f(H)=678, f(B)=1137\) and \(f(M)=1341,\) where \(N\) denotes no high school diploma, \(H\) a high school diploma, \(B\) a bachelor's degree, and \(M\) a master's degree. (Source: U.S. Bureau of Labor Statistics.) (a) Write \(f\) as a set of ordered pairs. (b) Give the domain and range of \(f\). (c) Discuss the relationship between education and income.

4 step solution

Problem 90

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(-2,5), Q(4,-3)$$

3 step solution

Problem 91

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$\frac{1}{3} x-\frac{1}{5} x \leq 2$$

4 step solution

Problem 91

If the sales tax rate is \(7.5 \%,\) write a function \(f\) that calculates the sales tax on a purchase of \(x\) dollars. What is the sales tax on a purchase of \(\$ 86 ?\)

3 step solution

Problem 91

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(-8,-2), Q(-3,-5)$$

2 step solution

Problem 92

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$\frac{3 x}{2}+\frac{4 x}{7} \geq-5$$

7 step solution

Problem 92

If college tuition costs \(\$ 192\) per credit and fees are fixed at \(\$ 275,\) write a formula for a function \(f\) that calculates the tuition and fees for taking \(x\) credits. What is the total cost of taking 11 credits?

5 step solution

Problem 92

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(-6,-10), Q(6,5)$$

5 step solution

Problem 93

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$\frac{x-2}{2}-\frac{x+6}{3}>-4$$

5 step solution

Problem 93

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(9.2,3.4), Q(6.2,7.4)$$

6 step solution

Problem 94

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$\frac{2 x+3}{5}-\frac{3 x-1}{2}<\frac{4 x+7}{2}$$

7 step solution

Problem 94

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(8.9,1.6), Q(3.9,13.6)$$

6 step solution

Problem 95

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$0.6 x-2(0.5 x+0.2) \leq 0.4-0.3 x$$

6 step solution

Problem 95

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(13 x,-23 x), Q(6 x, x), x>0$$

8 step solution

Problem 96

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$-0.9 x-(0.5+0.1 x)>-0.3 x-0.5$$

5 step solution

Problem 96

Find (a) the distance between \(P\) and \(Q\) and (b) the coordinates of the midpoint \(M\) of the segment joining \(P\) and \(Q\). $$P(12 y,-3 y), Q(20 y, 12 y), y>0$$

7 step solution

Problem 97

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$-\frac{1}{2} x+0.7 x-5>0$$

5 step solution

Problem 97

Suppose that \(P\) is an endpoint of a segment \(P Q\) and \(M\) is the midpoint of \(P Q .\) Find the coordinates of endpoint \(Q\). $$P(7,-4), M(8,5)$$

5 step solution

Problem 98

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$\frac{3}{4} x-0.2 x-6 \leq 0$$

5 step solution

Problem 98

Suppose that \(P\) is an endpoint of a segment \(P Q\) and \(M\) is the midpoint of \(P Q .\) Find the coordinates of endpoint \(Q\). $$P(13,5), M(-2,-4)$$

5 step solution

Problem 99

Solve each inequality analytically. Write the solution set in interval notation. Support the answer graphically. $$-4(3 x+2) \geq-2(6 x+1)$$

4 step solution

Problem 99

Suppose that \(P\) is an endpoint of a segment \(P Q\) and \(M\) is the midpoint of \(P Q .\) Find the coordinates of endpoint \(Q\). $$P(5.64,8.21), M(-4.04,1.60)$$

5 step solution

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