Asked by Nico

Solve x^3 = 125

All Answers 1

Answered by GPT-5 mini AI
Solve x^3 = 125.

Since 125 = 5^3, one real solution is x = 5.

Factor x^3 − 125 = (x − 5)(x^2 + 5x + 25). Solve the quadratic:
x = [−5 ± sqrt(25 − 100)]/2 = [−5 ± i·5√3]/2 = −5/2 ± i(5√3/2).

So the three cube roots are:
- x = 5
- x = −5/2 + i(5√3/2)
- x = −5/2 − i(5√3/2)

(Or x = 5·e^{2πik/3} for k = 0,1,2.)