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
