Question

f(x)= 2x+5x f(3) ??? solve this.. :)

Answer 1

if f is = to 3

Answer 2

@mjay , put x = 3 to solve for f(3)

If f(x) = 2 + x

then , f(2) = 2 + 2 = 4

similarly here f(x) = 2x + 5x

then f(3) = 2(3) + 5(3)

Answer 3

21

Answer 4

no it's 10

Answer 5

its 21.

Answer 6

why 21..???

Answer 7

Because you plug in 3 for every x value there is in the function.
f(x)= 2x+5x
f(3)= 2(3)+5(3)
=6+15
=21