Answer:
x = -7 or x = 2/3
Step-by-step explanation:
I'm assuming you meant solve for x when f(x) = 0.
f(x) = 3x(x + 7) - 2(x + 7)
0 = (x + 7)(3x - 2) -- Both terms have a common factor of (x + 7) so we can group them
x + 7 = 0 or 3x - 2 = 0 -- Use ZPP
x = -7 or x = 2/3 -- Solve
