Problem 37 - Elementary Algebra

Question

Determine the slope and \(y\) -intercept of the lines. $$ 4 y=5 x+1 $$

Step-by-Step Solution

Answer

Answer: The slope of the line is $$\frac{5}{4}$$ and the y-intercept is $$\frac{1}{4}$$.

Step 1: Rearrange the equation to slope-intercept form

To rearrange the given equation $$4y = 5x + 1$$ to the slope-intercept form ($$y = mx + b$$), we need to isolate $$y$$ on one side of the equation. We can do this by dividing both sides of the equation by 4: $$ y = \frac{5x + 1}{4} $$ Now, the equation is in slope-intercept form.

Step 2: Identify the slope and y-intercept

With the equation in the slope-intercept form ($$y = mx + b$$), we can easily identify the slope ($$m$$) and y-intercept ($$b$$) from the coefficients. In this case, $$ m = \frac{5}{4} $$ and $$ b = \frac{1}{4} $$ Thus, the slope of the line is $$\frac{5}{4}$$ and the y-intercept is $$\frac{1}{4}$$.

Key Concepts

Determining Slope

Understanding how to determine the slope of a line is crucial for unraveling the behavior of linear equations in a coordinate system. The slope represents how steep the line is, and it shows the rate at which one variable changes in relation to another. In the slope-intercept form of a line, which is given as
\(y = mx + b\)
, the slope is represented by the variable \(m\).

To find the slope from an equation, look for the coefficient that is multiplying the variable \(x\) after the equation has been rearranged into slope-intercept form. If the original equation is not in this form, you might have to perform some algebraic manipulation first. In the exercise at hand, the slope of the line \(4y = 5x + 1\) was determined by first transforming it to \(y = \frac{5x + 1}{4}\), and then identifying the slope as \(\frac{5}{4}\). This indicates that for every one unit increase in \(x\), \(y\) increases by \(\frac{5}{4}\) units.

Identifying Y-Intercept

The y-intercept is another essential characteristic of the line, denoting the point where the line crosses the y-axis. This is where the value of \(x\) is zero. In the slope-intercept form \(y = mx + b\), it is the \(b\) term that marks the line's y-intercept.

To locate the y-intercept, you can set \(x\) to zero and solve for \(y\), or simply identify the constant term when the equation is in the correct form. Following our exercise, the y-intercept was found after rearranging the given equation into slope-intercept form, yielding \(b = \frac{1}{4}\). This y-intercept means that when \(x\) equals zero, the y-value will be \(\frac{1}{4}\), thus the line will touch the y-axis at the point \(0, \frac{1}{4}\).

Algebraic Manipulation

Algebraic manipulation involves techniques used to rearrange equations and expressions to a desired form or to isolate specific variables. This skill is particularly vital when solving for the slope and y-intercept of a line.

In the context of the given exercise, we needed to rearrange the equation \(4y = 5x + 1\) so that it took the form \(y = mx + b\) to identify the slope and y-intercept readily. This was achieved by dividing all terms of the equation by 4, a process that maintains the equality because the same operation is applied to both sides of the equation.

This kind of manipulation is not limited to simple division; it may include adding, subtracting, multiplying, or dividing terms on both sides of the equation, factoring, expanding, and dealing with fractions to achieve the desired form or to simplify expressions for easier interpretation.