Question

Factor the expression x^4+8x^2-20??

Answer 1

x^4+8x^2-20 ..?

Answer 2

Were doing some cubic stuff in class lol

Answer 3

its x^4+8x^2-20 @Algebraic!

Answer 4

substitute u =x^2

Answer 5

Start wit a substitution to make it simpler:
Let u = x^2, then u^2 = x^4. Now re3place the x's with the u's:
u^2 + 8u - 20
Can you factor that one?

Answer 6

@mathstudent55 Im not sure.... My teacher didnt really go over this so i have no idea. Would I pull out a 4?

Answer 7

u^2 + 8u - 20
is a quadratic... you've factored a lot of those by now I think....

Answer 8

what two number multiply to give -20 and add to give 8?

Answer 9

@Algebraic! 10 and -2

Answer 10

(u+10)(u-2) = (x^2 +10)(x^2 -2)

Answer 11

(x^2-2) is a difference of squares.. so you can factor that ...

Answer 12

@Algebraic! Okay so what would i do with the other equation?

Answer 13

(x^2+10) ? no real roots...