Ответ:\(2a+ac^2-a^2c-2c=(a-c)(2+ac)\). При \(a=\frac43, c=-\frac53\): \((3)(-\frac29)=-\frac23\).\(x^2y-y+xy^2-x=(xy-1)(x+y)\). При \(x=4,y=0.25\): \(0\cdot4.25=0\).