Question

Solve the equation after making the appropriate substitution. Need help!

Answer 1

Explanation:

First realize that

`(x^(1/3))^(2)=x^(2/3)`

Usually when you are asked to solve making a substitution you need to find substitute a term leaving a quadratic equation.

if you replace:

`x^(1/3)=u`

`u^(2)-3u-18 = 0 \\(u-6)(u+3)= 0 \\u = 6 \\u = -3 \\x^(1/3) = 6 => x = 6^(3) = 216\\x^(1/3) = -3 => x = (-3)^(3) = -27`