Question

a line passes through the points (-1, -18) and (3, 18). write its equation in slope - intercept form. write your answer using integers, proper fractions, and improper fractions in simplest form.

Explanation:

Step1: Calculate the slope

The slope formula is $m=\frac{y_2-y_1}{x_2-x_1}$. Substitute $(x_1,y_1)=(-1,-18)$ and $(x_2,y_2)=(3,18)$:
$m=\frac{18-(-18)}{3-(-1)}=\frac{36}{4}=9$

Step2: Find y-intercept $b$

Use slope-intercept form $y=mx+b$, substitute $m=9$ and point $(-1,-18)$:
$-18=9(-1)+b$
$-18=-9+b$
$b=-18+9=-9$

Step3: Write final equation

Substitute $m=9$ and $b=-9$ into $y=mx+b$.

Answer:

$y=9x-9$