Question

If f(x)=3x^2 +2 and g(x)= x^2 + 2x, what is f(g(x)) when x=2?

Answer 1

Explanation:

f(g(x))=3(x^2+2x)^2+2=3(x^4+2*x^2*2x+4*x^2)+2

=3x^4+3*4*x^3+12*x^2+2=

=3x^4+12x^3+12x^2+2 for x=2

=3*2^4+12*2^3+12*2^2+2=

=3*16+12*8+12*4+2

=48+96+48+2=

=144+50=194