A.a*2=u1*u2B.a*2=u1-u2C.a*2=u1/u2D.a*2=u1+u2
A.M1=1.4,M2=0.5030B.M1=2.5,M2=0.5130C.M1=3.6,M2=0.5230D.M1=4.7,M2=0.5330
A.272.14B.162.14C.212.14D.302.14