Answer:
C
Step-by-step explanation:
Given
cos x + = - cosx ( add cosx to both sides )
2cosx + = 0 (subtract from both sides )
2cosx = - ( divide both sides by 2 )
cosx = -
Since cosx < 0 then x is in the second/ third quadrant
x = ( )
= ← related acute angle
Hence
x = π - = ← second quadrant
or
x = π + = ← third quadrant