Explanation:
y³ (y² − 10) = -9y
Move everything to one side:
y³ (y² − 10) + 9y = 0
Factor out common term:
y (y² (y² − 10) + 9) = 0
Distribute:
y (y⁴ − 10 y² + 9) = 0
Factor:
y (y² − 1) (y² − 9) = 0
Solve:
y = 0, ±1, ±3
Since y > 0, the two possible values for y are 1 and 3.