1. The problem statement, all variables and given/known data Establish associative law of multiplication by considering absolute values and arguements. z1(z2z3)=(z1z2)z3 2. Relevant equations 3. The attempt at a solution I think I need to use r(costheta +isintheta) r1(costheta1+isintheta1)[r2r3(costheta2+isintheta2)(costheta3+isintheta3)]= Is this just a bunch of multiplying out and showing it's the same?