Question

If the graph of the line y = ax + b passes through the points (4,5) and (8,17), what is a - b?

Answer 1

10

Explanation:

To find a:

y2-y1/x2-x1

17-5/8-4

12/4

3

To find b:

y=3x+b

We replace y and x with (4,5)

5=3(4)+b

5=12+b

-7=b

3-(-7)

10

Answer 2

Your answer is y=3x-7

To solver this problem, use point-slope form.

y-y1=m(x-x1)

y-5=3(x-4)

y=3x-12+5

y=3x-7