计算:(1)(x-y+4xyx-y)•(x+y-4xyx+y)(2)1x2+3x+2+1x2+5x+6+1x2+7x+12.-数学

题目简介

计算:(1)(x-y+4xyx-y)•(x+y-4xyx+y)(2)1x2+3x+2+1x2+5x+6+1x2+7x+12.-数学

题目详情

计算:
(1)(x-y+
4xy
x-y
)•(x+y-
4xy
x+y
)

(2)
1
x2+3x+2
+
1
x2+5x+6
+
1
x2+7x+12
题型:解答题难度:中档来源:不详

答案

(1)(x-y+class="stub"4xy
x-y
)•(x+y-class="stub"4xy
x+y
)

=
(x+y)2
x-y
(x-y)2
x+y

=(x+y)(x-y)
=x2-y2;

(2)class="stub"1
x2+3x+2
+class="stub"1
x2+5x+6
+class="stub"1
x2+7x+12

=class="stub"1
(x+1)(x+2)
+class="stub"1
(x+2)(x+3)
+class="stub"1
(x+3)(x+4)

=
x2+7x+12+x2+5x+4+x2+3x+2
(x+1)(x+2)(x+3)(x+4)

=
3(x+2)(x+3)
(x+1)(x+2)(x+3)(x+4)

=class="stub"3
x2+5x+4

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