G(x)=3x+5
H(x)=4x
in the first one they asked for the multiplication of g and h
so you basically need to multiply the equations given
(3x+5)(4x) and that is 12x^2+20x
the second one is just adding both so it will be (3x+5+4x) add x’s with eachother you will get 7x+5
The thirst one is subtracting (3x+5-4x)
you will get -x+5