Question

I know where to even start these 3 problems
The given is this:Let f(x)=x^2+3 and g(x)=4x+2, evaluate the following.
c. 2*f(x)-g(x) =
d.f(g(4)) =
e.g(f(4)) =

Answer 1

huh? just do a direct substitution...
2*f(x)-g(x) = 2*(x^2+3)-(4x+2) = ...
f(g(4)) = f(4*4+2) = f(18) = ...
g(f(4)) = g(4^2+3) = g(19) = ...

don't be scared by all those parentheses...

Answer 2

f(x) = x² + 3

g(x) = 4 x + 2


c.

2 ∙ f(x) - g(x) = 2 ∙ ( x² + 3 ) - ( 4x + 2 ) = 2 x² + 6 - 4 x - 2 =

2 x² - 4 x + 4 = 2 ( x² - 2 x + 2 )

d.

g(4) = 4 ∙ 4 + 2 = 16 + 2 = 18

f(g(4)) = f (18) = 18² + 3 = 324 + 3 = 327

e.

f(4) = 4² + 3 = 16 + 3 + 19

g(f(4)) = g(19) = 4 ∙ 19 + 2 = 76 + 2 = 78

Answer 3

My typo.

f(4) = 4² + 3 = 16 + 3 = 19