If f(x)=2x10 ; g(x)=4x+20 what is the value of (f + g) (3) ?

1 Answer
Oct 29, 2015

(f+g)(3)=28

Explanation:

First method:

Add f(x)+g(x)

(2x10)+(4x+20)

Combine like terms.

=6x+10

Then substitute 3 for x.

=6(3)+10
=18+10
=28

Second method:

Substitute 3 into both functions individually.

f(3)=2(3)10
=610
=4

g(3)=4(3)+20
=12+20
=32

Then add the answers you get from substituting together.

=4+32
=28