19 sin(3π/2 + a) + 91 cos(3π+a), если cos a= -3/2

Question

19 sin(3π/2 + a) + 91 cos(3π+a), если cos a= -3/2

Answer 1

-19cos(a)-91cos(a)= -19/1 ×(-3/2)-91/1 × (-3/2)=57/2+273/2=330/2=165