Question

Solve the equation x^4-64=0

Answer 1

A

Explanation:

x^4-64=0

factor

(x^2+8)(x^2-8)=0

zero property

x^2+8=0, x^2-8=0

x^2=0-8-8,

x^2=-8,

x^2=0+8=8,

x^2=8,

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sqrt(8) & sqrt(-8),

gives you 2*sqrt(2) and -2*sqrt(2),

also, the square root of a negative number contains the imaginary number, i. Because sqrt(-1)=i, don't forget this formula.

So sqrt(-8)=2i*sqrt(2) and -2i*sqrt(2).

Answer 2

A

Explanation:

x^4=64

x^2= +- 8

x = +-sqrt2, x= +- i sqrt2