y = mx + b....m is the slope and b is the y intercept
slope(m) = 5...(4,0)...x = 4 and y = 0
now we sub our info into y = mx + b...we r looking for b, the y intercept
0 = 5(4) + b
0 = 20 + b
-20 = b
so ur equation is y = 20x - 20...but we need it in standard form
Ax + By = C
y = 20x - 20....subtract 20x from both sides
-20x + y = -20...multiply by -1 to make x positive
20x - y = 20 <== standard form
