Question

What is the solution to x(3)=−343

Answer 1

If the equation means x^3 = −343, then the real solution is x = −7, since (−7)^3 = −343.

(If you want all complex solutions: x = 7·e^{i(π+2πk)/3} for k = 0,1,2, i.e. x = −7 or x = 7(1/2 ± i√3/2).)