5.3_多项式的乘法拔高练习题(1)(含答案)
5.3 多项式的乘法(1)
◆基础训练
1.下列计算错误的是( )
A .(x+1)(x+4)=x 2+5x+4
B .(m -2)(m+3)=m 2+m -6
C .(y+4)(y -5)=y 2+9y -20
D .(x -3)(x -6)=x 2-9x+18
2.计算m 2-(m+1)(m -5)的结果正确的是( )
A .-4m -5
B .4m+5
C .m 2-4m+5
D .m 2+4m -5
3.计算(
2a -2b )(33
a b )+b 2的结果是( ) A .16a 2 B .16(a 2+5b 2) C .16(a 2-5b 2) D .16a 2+76
b 2 4.如果(x+q )(x+15
)的积中不含x 项,那么q 的值是( ) A .5 B .-5 C .15 D .-15 5.计算:
(1)(x+2)(x+3) (2)(3x -1)(2x -1)
(3)(x -3y )(x+7y ) (4)(5x+2y )(3x -2y )
6.计算:
(1)(x+2)(x -3) (2)(a -b )(m+2n )
(3)(x-2y)(y-x)(4)(2
3
x-
1
2
y)(
3
4
x+
2
3
y)
(5)(x-y)2(6)(a+b)(a-b)
7.当a=-1
3
时,求(a-4)(a-3)-(a-1)(a-3)的值.
◆综合应用
8.利用公式(x+a)(x+b)=x2+(a+b)x+ab计算:
(1)(x+1)(x+3)(2)(a-2)(a-5)(3)(a-y)(a+2)(4)(m+2)(m-3)(5)(ab-2)(ab+1)(6)(x-2y)(x+3y)
9.先化简,再求值:(x-1)(x+2)+(2x-1)(x+5)-3(x2-6x-1),其中x=31
2
.
10.解不等式,并把解集在数轴上表示出来.
x(x-1)+(x-1)(x+1)<2(x+1)(x+1).
◆拓展提升
11.若(x2+px+q)(x2-2x-3)展开后不含x2,x3项,求p,q的值.
参考答案
1.C 2.B 3.B 4.D
5.(1)x2+5x+6 (2)6x2-5x+1
(3)x2+4xy-21y2(4)15x2-4xy-4y2
6.(1)x2-x-6 (2)am-bm+2an-2bn (3)-x2+3xy-2y2
(4)1
2
x2+
5
72
xy-
1
3
y2?(5)x2-2xy+y2(6)a2-b2
7.-3a+9,10
8.(1)x2+4x+3 (2)a2-7a+10 (3)a2-5a-14 (4)m2-m-6 (5)a2b2-ab-2 (6)x2+xy-6y2 9.28x-4,94
10.x>-3
5
,图略
11.p=2,q=7