Question

What is the equation of a line that has a slope of -2/3 and passes through point (-3,-1)?

Answer 1

y = -(2/3)x - 3

To completely find the equation of the line, we have to find b, or the y-intercept. This is where the line intersects the y-axis, or the vertical axis.

To find b, we can substitute y and x with (-3, -1) because we know that this is a point which is satisfied by the equation of the line.

y = -(2/3)x + b

Substitute (x, y) with (-3, -1)

x --> -3

y --> -1

-1 = -(2/3)(-3) + b

-1 = 2 + b

b = -3

y = -(2/3)x - 3

Check our work. Just plug in the value of (-3, -1), and see if it works!

-1 = -(2/3)(-3) - 3

-1 = 2 - 3

-1 = -1

It works!