arEDU. com 教育网 解:().(xy)+(3xy (--÷3)·x2-2y 3-1 2 (2)(10a“bc)÷(5abc) (10÷5a 4-313-12-1 2ab 2 C
解: ) (3 ) 5 3 (1) ( 2 3 2 − x y x y 2 2 3 1 3) 5 3 ( − − = − x y 2 5 1 = − y (2) (10 ) (5 ) 4 3 2 3 a b c a bc 4 3 3 1 2 1 (10 5) − − − = a b c ab c 2 = 2
arEDU. com (3)(2x2y)-(-7xy2)÷(14 教育网 =8xy-(-7xy2)÷(14xy2 =-56x3y3÷(14x4y2) 32 x v (4)(2a+b)+÷(2a+b)2 =(2a+b) 4-2 =(2a+b)2=4a2+4ab+b
(3) (2 ) ( 7 ) (14 ) 2 3 2 4 3 x y − x y x y 8 ( 7 ) (14 ) 6 2 4 3 = x y − x y x y 56 (14 ) 7 5 4 3 = − x y x y 3 2 = −4x y 4 2 (4) (2a +b) (2a +b) 4 2 (2 ) − = a +b 2 = (2a +b) 2 2 = 4a + 4ab + b