2sin(40+x)*sin(x-50)+1=0

Question

2sin(40+x)*sin(x-50)+1=0

Answer 1

2*1/2(cos90-cos(2x-10))+1=0
-cos(2x-10)+1=0
cos(2x-10)=1
2x-10=360n
2x=10+360n
x=5+180n,n∈z