因式分x3-2x2+x=______.已知x+y=6,xy=-2,则1x2+1y2=______.-数学

题目简介

因式分x3-2x2+x=______.已知x+y=6,xy=-2,则1x2+1y2=______.-数学

题目详情

因式分x3-2x2+x=______.
已知x+y=6,xy=-2,则
1
x2
+
1
y2
=______.
题型:填空题难度:中档来源:不详

答案

x3-2x2+x,
=x(x2-2x+1),
=x(x-1)2;

∵x+y=6,xy=-2,
class="stub"x+y
xy
=class="stub"1
x
+class="stub"1
y
=-3,
两边平方得,class="stub"1
x2
+2×class="stub"1
x
class="stub"1
y
+class="stub"1
y2
=9,即class="stub"1
x2
+2×class="stub"1
xy
+class="stub"1
y2
=9
所以,class="stub"1
x2
+class="stub"1
y2
=10.
故答案为:x(x-1)2;10.

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