Question

If x=9 is a solution of the equation x² -a=0, which of the following is a solution of x^4 - a=0?

A: -81
B: -3
C: 0
D: 9
E: 81

Answer 1

x² - a = 0. If x = 9, then:

9² - a = 0  or 81 =a
So a= 81(E)