Question

solve x^4 -7x^2 =18

Answer 1

start with
\[x^4-7x^2-18=0\] and then factor

Answer 2

if it is not clear how to factor, think of it as
\[w^2-7w-18=0\] where \(w=x^2\)

Answer 3

so you cancelled out \[x ^{2}\]

Answer 4

no i replace \(x^2\) by \(w\) so i can replace \(x^4\) by \(w^2\)
it might help in factoring, but it is not really necessary

Answer 5

well now im confused..

Answer 6

can you factor
\[x^2-7x-18=0\]?

Answer 7

nope

Answer 8

i dont understand math at all

Answer 9

oh that is a problem then

Answer 10

because you cannot do this without factoring
your job is to come up with two numbers that, when multiplied together, give \(-18\) and when you add them you get \(-7\)
one is obviously positive, and the other negative

Answer 11

if you like i will tell you what they are

Answer 12

ok

Answer 13

-2 and 9?

Answer 14

@satellite73 ?