m = -3

y = mx + b

y =-3x + b

To solve SUBSTITUTE the point (4,-6), where x=4, y=-6and SOLVE for b

y = -3x + b

-6= -3(4) + b

-6= -12 + b ADD 12 to both sides

6= b

The y-intercept is 6

CHECK

The equation for the line in the form y = mx + b is:

y = -3x + 6

SUBSTITUTE the point (4, -6)

-6 = -3(4) + 6

- 6 = -12 + 6

-6 = -6 it checks out