Question 632190

y = 5x - 3

replace x with (x+3), plug back in:

y = 5(x+3)    -3

y = 5x + 15   -3

y = 5x + 12

y has increased by a net change of 15 overall, say if x was originally zero, y would have gone from -3 to 12, a net change of +15