Question

A line includes the points (-1, -10) and (1, 0). What is its equation in slope-intercept form?

Answer 1

The slope-intercept form:

$y=mx+b$

m - slope

b - y-intercept

The formula of a slope:

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

We have the points (-1, -10) and (1, 0). Substitute:

$m=\dfrac{0-(-10)}{1-(-1)}=\dfrac{10}{1+1}=\dfrac{10}{2}=5$

y = 5x + b

Put the coordinates of the point (1, 0) to the equation of line:

$0=5(1)+b$

$0=5+b$      subtract 5 from both sides

$-5=b\to b=-5$

Answer: y = 5x - 5