Question

Write the equation of the line containing the point (3, –2) and having a slope of 2 in slope-intercept form.

Answer 1

The slope-intercept form:

`y=mx+b`

m - slope

b - y-intercept

We have the slope m = 2 and the point (3, -2) → x = 3 and y = -2.

Substitute:

`-2=(2)(3)+b`

`-2=6+b` subtract 6 from both sides

`-8=b\to b=-8`

Substitute to the equation y = mx + b:

Answer: y = 2x - 8

Answer 2

Slope-intercept form:

y = mx + b

"m" is the slope, "b" is the y-intercept (the y value when x = 0 or (0,y))

You know m = 2, so you can plug it into the equation

y = 2x + b

To find "b", plug in the point (3, -2) into the equation

y = 2x + b

-2 = 2(3) + b

-2 = 6 + b

-8 = b

y = 2x - 8