Four polynomial functions are shown below:

f (x) = x3 + 3x2 - 4x - 12

g (x) = x3 - 3x - 2

p (x) = x2 + 3x + 2

t (x) = x2 + x - 2

Which of the following functions has 1 and - 2 as its zeros?

f (x)

g (x)

p (x)

t (x)

Easiest way is to subsitute 1 for x and evaluate then - 2 for x and evaluate

if they evaluate to 0 then they are roots

f (x)

if we did 1 for first one we get f (1) = - 12 so 1 is not a zero

g (x)

if we did 1 for g (x) we get g (1) = - 4, so 1 is not a zero

p (x)

if we did 1 for p (x) we get p (1) = 6 so 1 is not a zero

t (x)

if we did 1 for t (x) we get t (1) = 0, so 1 is a zero

try - 2

if we did - 2 for t (x) we get t (-2) = 0, so it is also a zero

t (x) is answer