Answer:
x = 0, π/2, π
Explanation:
One can only divide by a value that is non-zero. The division is invalid when sin(x) = 0, at x = 0 or π.
The equation should have been factored.
sin²(x) -sin(x) = 0
sin(x)(sin(x) -1) = 0
The zero product rule tells us the product will be zero for either factor being zero:
sin(x) = 0 ⇒ x = 0, π
sin(x) -1 = 0 ⇒ x = π/2
The solutions are ...
x ∈ {0, π/2, π}