Theory question 102
Indices and LogarithmsSolve x2/3 − 5x1/3 + 6 = 0
Show the model answer
Model answer
Let y = x1/3: y² − 5y + 6 = 0
(y − 2)(y − 3) = 0, y = 2 or y = 3
x = 2³ = 8 or x = 3³ = 27
Explanation
Substitute y = x1/3 to get a quadratic, then cube the answers.