Question

I need help with this math question can someone please help me?

If f(x)=2x^2-4x-3 and g(x)=(x-4)(x+4),find f(x)-g(x)
Answers:
4x+13
x^2-4x+13
3X^2-4x+13
-4x^2-4x+13

Answer 1

f(x) - g(x) = 2x^2 - 4x - 3 - (x-4)(x + 4)

first expand (x - 4)(x + 4) then subtract

Answer 2

How do I do that? @welshfella

Answer 3

(x + 4(x - 4) = x(x -4)+4(x - 4)

Answer 4

So is it like the foil method?? no? @welshfella

Answer 5

you can use the foil method if you prefer it

Answer 6

oh okay, so is the answer -4x^2-4x+13??

Answer 7

No
tell me what you get for (x+4)(x-4)

Answer 8

okay is it this \[x^2-16+4x+4x\]?

Answer 9

kind of what i got when i foiled them...
as you can see im not good in math at all @welshfella

Answer 10

nearly write
but its +4x - 4x

Answer 11

okay i see

Answer 12

so the result is x^2 - 16
so now we have
2x^2 - 4x - 3 - (x^2 - 16)

Note the parentheses around the x^2 - 16

Can you simplify this?

Answer 13

no i dont think so

Answer 14

you have to distribute the negative over the parentheses so -16 becomes -1*-16 = + 16

Answer 15

you completely lost me there 0_o

Answer 16

2x^2 - 4x - 3 - (x^2 - 16)
= 2x^2 - 4x - 3 - x^2 + 16

now simplify like terms and you have the answzer

Answer 17

3x^2-4x+13??

Answer 18

bring like terms together to make it easier

2x^2 - x^2 - 4x -3 + 16

Answer 19

what is 2x^2 - x^2 ?

Answer 20

i know this sounds childish but suppose x^2 = an apple what we have here is 2 apples take away one apple

Answer 21

leaving one apple, right?

Answer 22

right

Answer 23

2 apples - 1 apple = 1 apple
2x^2 - 1 x^2 = ?

Answer 24

0

Answer 25

?

Answer 26

no
x^2 = apple
instead of an apple write x^2

Answer 27

wait so is it x^2-4x+13???

Answer 28

yes

2 x^2 - x^2 = x^2

we could write 1 x^2 but the 1 is usually left out


2x^2 and x^2 are like terms so you can subtract the

Answer 29

omg thank you so much for all of the help!! and for not giving up on me on this question @welshfella

Answer 30

yw

Answer 31

think of algebra as a kind of shorthand will help
remember you can only simplify like terms

4x + x^2 cann ot be simplified because they are not like terms
but 2x and 5x can - 2x + 5x = 7x

Answer 32

* 2x + 5x = 7x ( i didnt mean to put the negative there)

Answer 33

Thank you for that tip i will use it with any other math questions @welshfella

Answer 34

if you dont mind could you help me with more? @welshfella

Answer 35

sorry I have to go right now