Question

A line has a y-intercept at (0,−15) and contains the point (−4,−3). What is the equation of the line in slope-intercept form?

Answer 1

Answer: $y=-3x-15$

Step-by-step explanation:

The equation of the line in Slope-Intercept form is:

$y=mx+b$

Where "m" is the slope and "b" the y-intercept.

Since the given line  has a y-intercept at (0,-15), then:

$b=-15$

The formula for calculate the slope is:

$m=\frac{y_2-y_1}{x_2-x_1}$

Knowing that the given line contains the points (0,-15) and (-4,-3), we can calculate the slope. This is:

 $m=\frac{-15-(-3)}{0-(-4)}=-3$

Substituting values into $y=mx+b$, we get that the equation of the line in Slope-Intercept form is:

$y=-3x-15$