Math Graphing Question

Question

The line l1 passes through the points (3,-3) and (-5,2). The line is the graph of the equation Ax + By = C, where A, B, and C are integers with greatest common divisor 1, and A is positive. Find A + B + C.

Answer 1

First you need to find the slope:
m = (2 - -3)/(-5 - 3) = -5/8

Plug one of the points in Point-Slope Equation:
y - y₁ = m (x - x₁)
y - 2 = -5/8 (x + 5)

Rearrange the equation to make it in Standard Form:
y - 2 = -5/8 (x + 5)
y - 2 = -5x/8 - 25/8
8y - 16 = -5x - 25
5x + 8y = -9

Find A + B + C
5 + 8 + (-9) = 4

 

Let me know if you have any questions! I hope this helps!