Question

x^3-9x^3/2+8=0

Answer 1

(u-8)(u-1) having trouble with steps that follow

Answer 2

let u = x^(3/2) and form a quadratic in u

Answer 3

x^(3/2) = 8
x = 8^)2/3) = 4

Answer 4

Okay, so I guess my problem is this: if u=8 and u=1 then u is x^3/2 correct? So once I get that, what do I do with the ^3/2?

Answer 5

[x^(3/2])^(2/3) = x
so you take RHS to power 2/3

Answer 6

[x^(3/2)]^(2/3) = 8 ^(2/3)

Answer 7

8^(2/3) = square of cube root of 8 = 2*2 = 4

Answer 8

Thank you.

Answer 9

yw