b) $N=\cos(180^0-x)-2\sin(180^0-x)+\cos x+2\sin(90^0-x)=$$-\cos x -2\sin x+\cos x+2\cos x=2\cos x- 2\sin x$
b) $N=\cos(180^0-x)-2\sin(180^0-x)+\cos x+2\sin(90^0-x)=-\cos x -2\sin x+\cos x+2\cos x=2\cos x- 2\sin x$
b) $N=\cos(180^0-x)-2\sin(180^0-x)+\cos x+2\sin(90^0-x)=
$$-\cos x -2\sin x+\cos x+2\cos x=2\cos x- 2\sin x$