# Solve by factoring: Find f(-2) for f(x) = 3^2 + 5x - 2

#### Missy

##### New member
Can someone guide me in the right direction to figuring out this problem I don't know where to begin.

if f(x) = 3^2 +5x -2 find f(-2)

would appreciate any help you can give me. Need to pass this math class to get my degree
Missy

#### r_yackel

##### New member
Re: Solve by factoring

Missy said:
Can someone guide me in the right direction to figuring out this problem I don't know where to begin.

if f(x) = 3^2 +5x -2 find f(-2)
anywhere you see a x plug in a -2
so you then have:
3^2+5(-2)-2

does that help

#### Subhotosh Khan

##### Super Moderator
Staff member
Re: Solve by factoring

Missy said:
Can someone guide me in the right direction to figuring out this problem I don't know where to begin.

if f(x) = 3^2 +5x -2 find f(-2)<<< could it be 3x^2 + 5x - 2

would appreciate any help you can give me. Need to pass this math class to get my degree
Missy

#### Missy

##### New member
Re: Solve by factoring

yes that is what I meant sorry about the typo

yes the question was if f(x) = 3x^2 +5x - 2 find f(-2) thank you for correcting me I had really gotten confused myself

again thank you,
Missy

#### r_yackel

##### New member
Re: Solve by factoring

Missy said:
yes that is what I meant sorry about the typo

yes the question was if f(x) = 3x^2 +5x - 2 find f(-2) thank you for correcting me I had really gotten confused myself

again thank you,
Missy
just substitute -2 everywhere you see an x
the solve

#### Missy

##### New member
Re: Solve by factoring

ok you said to put -2 anywhere that I see an x so does this mean that

3(-2) + 5 (-2) -2

so then this would be -6 +-10 -2

I am really confused here can you explain a little more

Missy

#### r_yackel

##### New member
Re: Solve by factoring

Missy said:
ok you said to put -2 anywhere that I see an x so does this mean that

3(-2) + 5 (-2) -2

so then this would be -6 +-10 -2

I am really confused here can you explain a little more

Missy
Okay so you started with f(x)= 3x^2 + 5x - 2
f(x) is a function of x
so
f(-2) means that you would replace all the x's with -2
which gives you
f(-2)= 3(-2)^2 + 5(-2) - 2
= 3(4) + (-10) -2 squared the -2
= 12-10-2
= 0
if it was f (-10) then you would have
f(-10) = 3(-10)^2 + 5(-10) - 2
= 3(100) + (-50) -2
= 300-50-2
= 248