a) 12×(23−56)2 = 12×(46−56)2 = 12×(−16)2 = 12×136 = 13.
b) 4×(−12)3−2×(−12)2+3×(−12)+1 = 4×−18−2×14+−32+1=−12−12+−32+22=−32