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12.2.3多项式与多项式相乘1.(2x+3)(3x-2)=_.2.(_+2y)(2x-_)=6x2-5xy-6y23.若(x+3)(x-5)=x2+Ax+B,则A=_,B=_.4.方程(x-1)(2x+1)=(2x-1)(x+2)的解为_.5.(x+y)(x2-xy+y2)=_.6.下列计算错误的是( )A.(x+1)(x+4)=x2+5x+4 B.(y+4)(y-5)=y2+9y-20C.(m-2)(m+3)=m2+m-6 D.(x-3)(x-6)=x2-9x+187.若(x-4)(x+8)=x2+mx+n,则m,n的值分别为( ) A.4,32 B.4,-32 C.-4,32 D.-4,-328.若(x-4)(M)=x2-x+N,则( )A.M=x+3,N=-12 B.M=x-3,N=12; C.M=x+5,N=-20 D.M=x-5,N=209.不等式(x+1)(x-2)x(x+2)的解集是( )A.x; C.x-10.下列各式:(2a+1)(2a-1)=4a2-a-1;(a-b)(a+b)=a2-ab+b2;(x-2y)( 3x+y)=3x2-5xy-2y2;(m+2)(3m-1)=3m2+6m+12中,错误的有( )个 A.1 B.2 C.3 D.411.当a=时,将(a-4)(a-3)-(a-1)(a-3)化简后,此代数式的值是( ) A. B.-6 C.0 D.812.计算：5a(a2+2a+1)-(2a+3)(a-5) 13.计算：(3x-1)(2x+3)-(x+3)(x-4)14.解方程: (2x2-3)(x+4)=x-4+2x(x2+4x-3)15.解不等式: (3x+4)(3x-4)9(x-2)(x+3)16.有一种打印纸长为acm,宽为bcm,在打印某种文挡时,设置的上下页边距均为2.5cm,左右页边距均为2.8cm,则一张这样的打印纸实际使用的面积是多大?参考答案：1.6x2+5x-6 2.3x，3y3.-2,-154.x=5.x3+y36.B 7.B8.A9.C10.C11.D12.解:原式=5a3+10a2+5a-(2a2-10a+3a-15)=5a3+10a2+5a-2a2+10a-3a+15=5a3+8a2+12a+15.13.解:原式=6x2+9x-2x-3-(x2-4x+3x-12)=6x2+7x-3-(x2-x-12)=6x2+7x-3-x2+x+12=5x2+8x+9.14.解:2x3+8x2-3x-12=x-4+2x3+8x2-6x, 2x3+8x2-3x-x-2x3-8x2+6x=-4+12, 2x=8,x=4.15.解:9x2-12x+12x-169(x2+3x-2x-6), 9x2-169x2+9x-54, 9x2-9x2-9x-54+16, -9x-38,x.16.
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