Question

For f(x) = 3x + 4, find f(2) and find x such that f(x) = 17

Answer 1

f(x) = 3x+ 4
⇒ f(2)= 3*2+ 4= 10
The basic idea is that you replace all x values with 2 to find f(2).

f(x) = 17
⇒ 3x+ 4= 17 (for f(x)= 3x+ 4)
⇒ 3x= 17-4
⇒ 3x= 13
⇒ x= 13/3
⇒ x= 4 1/3

f(2)= 10
f(x)=17 when x= 4 1/3

Hope this helps~