... sinh c quy tc SGK (1 3). GV: p dng quy tc khaiphng mt tớch thỡ:36,0.25 .9 = ? 40.810= ?GV: Cho hc sinh thc hin ?2Hc sinh c quy tc SGK (1 3). HS: 36,0.25 .9 = 3.5.0,6 = 9 40.810= 4.100.81= ... ngthc (a b)2 ?GV: Vy ( )213 = ?GV: Theo cõu a, ta cú : ( 13)2 = 324vy 324= ?Bài 11 SGKHS: (a b)2 = a2 2ab + b2Bi 10: Chng minh:a) ( 13)2 = 324.Ta cú VT = ( 13)2 ... 324.Ta cú VT = ( 13)2 = 13232+. =324= VPVy ( 13)2 = 324.HS: 324= ( 13)2 = 13 = 3- 1( do 3 > 1).Vy VT = ?b) ( )31333242= =13 - 3 = 1313=Vy 13224=Bài...