DO THEM FOR BRAIN Qs 5,6,7 pls

PLS DONT MAKE ME REPORT HAHAHA >:D

Which expression is equivalent to 3^3 + 2^2?

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

Determine if the solution set for the system of equations shown is the empty set, contains one point or is infinite. x + y = 5 x + y = 7 {} 1 solution infinite