Q7. - Algebra 1

Question

Define a variable, write an inequality, and solve each problem. Check your solution. 

A number decreased by 4 is more than $-1$.

Step-by-Step Solution

Answer

The variable is x is and the inequality equation is $x-4>-1$. The solution for the inequality is $x>3$.

Step 1. State the concept for inequality.

To graph the endpoint with strict inequality < or >, use the open parenthesis or a hollow circle at that endpoint.

To graph the endpoint with inequality symbol $\le \text{ or }\ge$, use the bracket or a solid circle at that endpoint.

 Properties of inequality:

width="181" style="max-width: none; vertical-align: -36px;" $$\begin{gathered} 1.b\le c\Rightarrow b\pm a\le c\pm a \\ 2.b\le c\Rightarrow ab\le ac,\text{ if }a>0 \\ 3.b\le c\Rightarrow ab\ge ac,\text{ if }a<0 \end{gathered}$$

Step 2. Write the inequality for the given condition.

Let the number be x.

A number decreased by 4 is more than $-1$:

 $x-4>-1$

 

Step 3. Solve for x.

Solve for x  in the inequation $x-4>-1$

$$\begin{gathered} x-4>-1 \\ x-4+4>-1+4 \\ x>3 \end{gathered}$$

Step 4. Check the solution when x = 5 .

Put the value of x as 5.

$$\begin{gathered} x-4>-1 \\ 5-4>-1 \\ 1>-1 \left[\text{True Statement}\right] \end{gathered}$$ 

Thus, the solution of the inequality equation $x-4>-1$ is $x>3$.