Question

Simplify.
x(4-3x)+4(x^2+1)/x^2-4

Answer 1

\[\frac{ x(4-3x)+4(x ^{2}+1) }{ x ^{2}-4 }\]

Answer 2

@satellite73 I'm so sorry :/ I've been having yu hold my hand thru all these problems

Answer 3

donkey work if ever i saw it
http://www.wolframalpha.com/input/?i=%28x%284-3x%29%2B4%28x^2%2B1%29%29%2F%28x^2-4%29

Answer 4

but we can still work it out step by step
first expand
then combine like terms
then factor
then cancel a bunch
ready ?

Answer 5

Ready

Answer 6

\[\frac{ x(4-3x)+4(x ^{2}+1) }{ x ^{2}-4 }\]
\[=\frac{ 4x-12x^2+4x^2+4 }{ x ^{2}-4 }\] is a start

Answer 7

The numerator, wouldn't it just be \[4x-3x ^{2}\]
instead of \[4x-12x ^{2}\]

Answer 8

yeah i screwd it up

Answer 9

\[=\frac{ 4x-3x^2+4x^2+4 }{ x ^{2}-4 }\]

Answer 10

so you get
\[\frac{x^2+4x+4}{x^2-4}\] factor the top on bottom
you good with that?

Answer 11

both factor very easily, even i can do it

Answer 12

Haha :) give me a minute

Answer 13

no do it instantly in your head!

Answer 14

\[\frac{ (x+2)(x+2) }{ (x+2)(x-2) }\]

Answer 15

..I'm a slow math person shush

Answer 16

\[\frac{ (x+2) }{ (x-2) }\]

Answer 17

if you can do that other factoring you can certainlyi recognize a perfect square \(x^2+4x+4=(x+2)^2\) and the difference of two square \(x^2-4=(x+2)(x-2)\) when you see them

Answer 18

and yes you get what you said
too bad though

Answer 19

Too bad?

Answer 20

because problems like these lead you to believe that whenever you see a fraction like that (in some future real math class) that you will be able to factor and cancel
in reality you can rarely do it, but since you have been trained to think that everything goes, you may be tempted to cancel even when you cannot

Answer 21

just saying
if watch out in the future
guard against cancelling incorrectly
it is a common mistake

Answer 22

Alrighty, I'll keep that in mind. Thanks! :)

Answer 23

you done?