Question

Look at the graphs on the left hand side and match them with the corresponding slope-intercept equation form.

• A. y = 3x + 2
• B. 0.4y = -0.4x + 2
• C. 0.5y = -1x + 2

Answer 1

Let's find the slope and y-intercept of the given graphs.

Consider Graph 1:


$\text{Slope}=\frac{\text{Positive rise}}{\text{Positive run}}=\frac{3}{1}=3$

Value of y-intercept = 2

Substitute the values in slope-intercept form, y = mx + c

$\text{We get:}y=3x+2$


Consider Graph 2:


$\text{Slope}=\frac{\text{Negative rise}}{\text{Positive run}}=\frac{-2}{2}=-1$

Value of y-intercept = 5

Substitute the values in slope intercept form: y = mx + c

We get: y = -x + 5

$y=-x+5$
[Dividing both sides by 2.5, we get]

$\Rightarrow \frac{y}{2.5}=\frac{-1}{2.5}+\frac{5}{2.5}$

$\Rightarrow 0.4y=-0.4x+2$

So, equation for the second graph can be written as:
$0.4y=-0.4x+2$

Consider Graph 3:


$\text{Slope}=\frac{\text{Negative rise}}{\text{Positive run}}=\frac{-2}{1}=-2$

Value of y-intercept = 4

Substitute the values in slope intercept form: y = mx + c

We get: y = -2x + 4

$y=-2x+4$
[Dividing both sides by 2, we get]

$\Rightarrow \frac{y}{2}=\frac{-2}{2}+\frac{4}{2}$

$\Rightarrow 0.5y=-1x+2$

So, equation for the third graph can be written as:
$0.5y=-1x+2$