Question

What substitution should be used to rewrite x8 – 3x4 + 2 = 0 as a quadratic equation?
A.)u=x^2
B.)u=x^4
C.)u=x^8
D.)ux^16

Answer 1

look at the middle term

can you rewrite the leading term \[x^8\]

using the middle term \[x^4\]

Answer 2

b?

Answer 3

or c?

Answer 4

your 1st choice is best as

and using the index law for power of a power you get

\[x^8 = (x^4)^2\]