Question 1154342
2sin^2 x+15cosx-9=0


2(1-cos^2x) +15 cosx -9=0

2-2cos^2x +15cosx -9=0

2cos^2x -15cosx +7=0

2cos^2x -14cosx-cosx +7=0

2cosx(cosx-7)-1(cosx-7)=0

(cosx-7)(2cosx-1)=0

cosx =7 , or cos x =1/2