x-intercepts at (−3,0) and (1,0).

x = −3 or x = 1
x + 3 = 0 or x − 1 = 0
(x + 3)(x − 1) = 0

At the x-intercept, y = 0.

y = (x + 3)(x − 1) or y = x² +2x − 3

Use the same strategy as part (a) to solve part (b).