Step-by-step explanation:
a. f(0) = 0²+4(0)-12 = -12.
b. f(2) = 2²+4(2)-12 = 4+8-12 = 0.
c. x²+4x-12 = 0. Factors are +6 & -2
x²-2x+6x-12 = 0
x(x-2)+6(x-2) = 0
x+6 = 0 or x-2 = 0.
x = -6 or x= 2.
d. x²+4x-12 = 20
x²+4x-12-20 = 0
x²+4x-32 = 0 ,factors are +8 & -4.
x²-4x+8x-32 = 0
x(x-4)+8(x-4) = 0
x+8 = 0 or x-4 = 0
x = -8 or x = 4.
