北师大版初一数学下册平方差公式课后习题

北师大版数学七年级下册第一章1.5平方差公式课时练习2 2 2 2A . x -6y B . x -yC . x2- 36y 2D .2 236x -y5. ( 2x+y2 ) (2x-y2 )等于（）八242224D .,22A . x - y B . x - yC . 4x -y4x -y6.下面计算正确的是（)A.( a+b)( a-b)=2a+2bB.b5 + b5 =b10C.x5 x5 = x257.卜面计算错误的是（)2 2 2A.(y- z)(y+z)=y - z B.(m-n)(m+n) =n -mC.x52025 x = xD.y3D.(y-z)(y+z)=y2-z25 8 y =y、选择题1.(2x+1)(2x-1)等于()A.4x2-1B . 2x2-1C .x2-1D . 2x2+12.(x+5y)(x-5y)等于()3.(m+5)(m-5)等于()A.2 5 .m - 5B . m2-y2C .2 2m - 25 D . 25m - 54.(x+6y)(x-6y)等于()8. (2y-3z)(2y+3z)等于()”22r2c2_,2c222A. y - z B.2y - 3z C.4y-9z D . y -z9. (y+3z)(3z-y)等于()10. (x+3ab)(x-3ab)等于()2 2 2 2 2 2 2 2 2 2A.x -9a b B.x - 9ab C. x -ab D. x - a b2 2 2 211. (c+a b )(c- a b )等于()A , 2 4 22,2A.c - ab B. c -a b C.c -ab D. c - a b2 8B.c - a2224C.c - a D . c -a12. (c2)2+ ( a2) 2八.228A c- a B.4c -a(c2)2- (a2)2等于()8 8C.c -a13. (d+f) ( d-f)等于().332. 25566A d-f B.d - f Cd - f5 D. d - f二、填空题1. (5+x2) (5-x2)等于 ;2. (-x+2y) (-x-2y)等于 ;3. (-a-b) ( a-b)等于 ;二、计算题2 21. ( a- b) (a+b) ( a +b )2 22. ( 3a-b) ( 3a+b) - (a +b )