Question

A line passes through the points (-20, 4) and (-15, 8).

Calculate the slope of the line - simplify answer if possible. (If the slope is undefined, enter "DNE")
Then, write the equation of the line.

Answer 1

The slope is 4/5

y = 4/5x + 20

Explanation:

Slope:

Change in y over the change in x

(4 - 8) / -20 - -15

-4 / -20 + 15

-4 /-5

4 / 5

Equation of the line:

You could use either point given. I am going to use the point (-20,4) I will use -20 for x and 4 for y. I will use 4/5 as the slope. I will need to solve for the y-intercept

y = mx + b

4 = (4/5)(-20) + b

4 = -16 + b Add 16 to both sides

20 = b

The equation will be

y = 4/5x + 20