Question

If f(x) = 2x2 + 3, find f(3).

Answer 1

@phi

Answer 2

i need help please

Answer 3

f(3) means that you take the right hand side and put 3 where you see the "x"

Answer 4

when you see f(x) = expression and they want f(3)
that is short-hand for
everywhere you see x, replace it with a 3
then do the arithmetic

Answer 5

yes

Answer 6

31
15
21
39

Answer 7

So, you square the 3, then multiply that answer by 2. Now, take that last answer and add 3.

Answer 8

you should write it
as
2x^2 + 3
the up arrow means to the power

remember that x^2 is short for x times x

Answer 9

i think my answers is 15

Answer 10

I think you are guessing

Answer 11

you should already know this, but
2x^2+3 is the same as
2*x*x+3
(where * means multiply and + means add)
now replace the x's with 3's
what do you get?

Answer 12

31

Answer 13

2*x*x+3
replace the x's with 3's
what do you get?

do you know how to replace x with 3?

Answer 14

39

Answer 15

here is an example of replacing x with 3:

say we have x+4
wherever I see x, I make it a 3: 3+4
can you do that with

2*x*x+3

Answer 16

okey is 21