Ответ:

2sin²x+3cosx-3=0

2(1-cos²x)+3cosx-3=0

cosx=y

2(1-y²)+3y-3=0

y=1/2, y=1

cosx=1

x ∈ {2πk}, k ∈ Z

cosx=1/2

x ∈ {2πk-π/3, 2πk+π/3}, k ∈ Z

sinx<0

x ∈ {2πk+π/3}, k ∈ Z