the slope -4, and the line passes through the (4,-3).

Question

Write the equation using slope intercept form

My answer was y=-4x+48

Answer 1

Hi Damon,

You can check your answer by plugging in the point to the equation. The point (x=4, y=-3) would look like this plugged into your equation: (-3)= -4(4)+ 48, or -3= -16+48, or -3= 32. When plugging these numbers in, the equation is not equal on both sides, meaning that the answer you gave wouldn't work here.

To find the correct answer, we need to look at the formula for a straight line: y=mx+b where m= the slope of the line and b= the y intercept. We know from the problem that the slope must be equal to -4, leaving us with y= -4x +b. From here you can substitute the given point in the equation and solve for b.

-3= -4(4) +b

-3= -16+b

+16 +16

13= b

This tells us that b=13, now we simply substitute that into the formula.

The solution to your question is y=-4x+13