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

Guest Nov 22, 2018

#1**0 **

First, find the slope = rise/run = (y1-y2)/(x1-x2) = (5-17)/ (4-8) = (-12)/-4 = 3

This is 'a'

So the line , so far looks like

y = 3 x + b Now, let's put one of those x, y points in there to find 'b'

5 = 3(4) + b

5-12 = b b = -7

So the equation for this line is y = 3x -7 and a-b = 3-(-7) = 3 + 7 = **10**

ElectricPavlov Nov 22, 2018