Question

HELP PLEASE

using f (x)=7x-5 and g (x)= 4x , What is f (2)- g (4)



A)7

B)-7

C)9

D)-9

Answer 1

f(2)=7(2)-5=14-5=9
g(4)=4(4)=16
f(2)-g(4)=9-16=-7

f(2)-g(4)=-7
B

Answer 2

Do you see that when we change

f(x) = 7x - 5

to

f(2) = 7(2) - 5

we are simply saying to substitute in 2 for x? Well that is what we are doing:

f(2) = 7(2) - 5

f(2) = 14 - 5

f(2) = 9

Now we find g(4) the same way:

g(x) = 4(x)

g(4) = 4(4)

g(4) = 16

Now we find the difference of the two functions:

f(2) - g(4)

9 - 16

-7

So, the answer is B.