Question Video: Solving a Cubic Equation Mathematics • Second Year of Preparatory School

Video Transcript

Solve the cubic equation 𝑥 cubed equals eight for all rational numbers.

We recall that a rational number is a number that can be expressed as the quotient or fraction of two integers. In this question, we need to solve the equation 𝑥 cubed equals eight and we will do so by firstly taking the cube root of both sides. We know that the cube root of 𝑥 cubed is simply equal to 𝑥. And since two cubed is equal to eight, the cube root of eight is equal to two. The solution to the cubic equation 𝑥 cubed is equal to eight is therefore 𝑥 is equal to two.