(1)分解因式:4a(x-y)-2b(y-x)(2)用简便方法计算:20012-4002+1(3)已知x2+2x-1=0,求(3x-2)(3x+2)-2x(x-1)-(2x-1)2的值(4)已知:x=

题目简介

(1)分解因式:4a(x-y)-2b(y-x)(2)用简便方法计算:20012-4002+1(3)已知x2+2x-1=0,求(3x-2)(3x+2)-2x(x-1)-(2x-1)2的值(4)已知:x=

题目详情

(1)分解因式:4a(x-y)-2b(y-x)
(2)用简便方法计算:20012-4002+1
(3)已知x2+2x-1=0,求(3x-2)(3x+2)-2x(x-1)-(2x-1)2的值
(4)已知:
x=2
y=-
1
2
x=2
y=
1
2
是关于x、y的二元一次方程ax+by=3的两个解,求ba+ab的值.
题型:解答题难度:中档来源:不详

答案

(1)原式=4a(x-y)+2b(x-y)=(4a+2b)(x-y);
(2)原式=20012-2×2001+1=(2001-1)2=20002=4000000;
(3)原式=9x2-4-2x2+2x-4x2+4x-1=3x2+6x-5,
当x2+2x-1=0,即x2+2x=1时,原式=3(x2+2x)-5=3-5=-2;
(4)将
x=1
y=-class="stub"1
2
x=2
y=class="stub"1
2
代入方程得:
a-class="stub"1
2
b=3
2a+class="stub"1
2
b=3

解得:a=2,b=-2,
则原式=4-4=0.

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