Can someone tell me if I got this problem correct and if not, what did I do wrong?

For the pair of functions, f(x)= 3x and g(x) =2x^2-4x+5. Find the following:
(a) ( f o g) (x)
(b) (f o g) (-4)
(c ) (g o f) (x)
(d) (g o f) (-4)

My answers:

a. 6x^2-12x+15
b. 39
c. 18x^2-12x+5
d. -19

Question

Can someone tell me if I got this problem correct and if not, what did I do wrong?

For the pair of functions, f(x)= 3x and g(x) =2x^2-4x+5. Find the following:
(a) ( f o g) (x)
(b) (f o g) (-4)
(c ) (g o f) (x)
(d) (g o f) (-4)

My answers:

a. 6x^2-12x+15
b. 39
c. 18x^2-12x+5
d. -19

raden · Answer

a and c were right, but b and d still incorrect

raden · Answer

( f o g) (x) =  6x^2-12x+15
so, ( f o g) (-4) =  6(-4)^2 - 12(-4) + 15 = 6(16)+48+15 = 96+48+15=159

raden · Answer

(g o f) (x) = 18x^2-12x+5
(g o f) (-4) = 18(-4)^2-12(-4)+5 = 18(16)+48+5 = 288+48+5 = 341

anonymous · Answer

I see what I did wrong,  thank you for your help

raden · Answer

yw