Question

x/(x^2 - 2) = 2/(3x + 4) solve the proportion

Answer 1

we can "cross multiply" and then collect the terms to one side and solve a quadratic i believe

Answer 2

uh ok can you do that for me I'm taking a pretest so i haven't learned this yet

Answer 3

the pretest is the place TO learn it :)

Answer 4

please i need a good grade on this

Answer 5

\[\frac{a}{b}=\frac{c}{d}\to \ ad=bc\]

Answer 6

thats the essense of a cross multiply

Answer 7

um ok i'll try that so x(3x+4)= 2(x^2 - 2)

Answer 8

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

i agree so far; now lets distribute thru on each side ...

Answer 9

\[x(a+b)\to \ ax+bx\]
is distribution

Answer 10

ok so 4x + 4x = 2x^2 - 4 ???

Answer 11

almost; that 3xx kinda snuck away from you :)

3xx+4x = 2x^2 - 4

3x^2 +4x = 2x^2 - 4

now just move all the terms to one side using the appropriate adds and subtracts

Answer 12

3x^2 +4x = 2x^2 - 4
-2x^2 +4 -2x^2+4
------------------------
x^2 +4x +4 = 0

Answer 13

now i do something with like quadratic equation right?

Answer 14

yes, and depending on how familiar you are with them this can be easy or tricky ...

Answer 15

it factors nicely tho if your comfy with that

Answer 16

yeah i don't really remember how to do it

Answer 17

yeah, it takes practice :)

that end is a 4; we need the factors of 4: 1*4
2*2

the middle number is a 4; we need a set of factors from that first part that ADD up to 4

1+4 = 5 ; not it
2+2 = 4 ; that one will do just fine

split the quadratic into its component parts and fill in our numbers

(x+2) (x+2) = 0 is then what we solve

Answer 18

when x=-2 we get:

(-2+2) (-2+2) = 0

0(0) = 0

0=0


so when x=-2 is the solution to all our problems .... in this case :)

Answer 19

oh yesss now i remember so x= 2 and x = -2 ???

Answer 20

or is it just x= -2

Answer 21

just x=-2 ... thats the only thing that will fit

Answer 22

if we try x=2

(2+2)(2+2)=0

4(4) = 0

16=0

just doesnt fit

Answer 23

okay thanks can u answer my other question. its the last question i asked.

Answer 24

i can give it a shot