For x 0, which expression is equivalent to √(9x⁴)?

Question

For x > 0, which expression is equivalent to √(9x⁴)?

Accepted Answer

A. 3x². Take the square root of each factor: √9 = 3 and √(x⁴) = x², since (x²)² = x⁴. So √(9x⁴) = 3x².

Answer

B. 9x² — √9 is 3, not 9. Only the exponent was halved; the coefficient needs its square root too.

Answer

C. 3x⁴ — √(x⁴) is x², because squaring x² gives x⁴. The exponent halves under a square root.

Answer

D. 81x⁸ — 81x⁸ is (9x⁴)² — the expression was squared instead of square-rooted.

Advanced Math practice question