若x=30,那么xx-3-x+6x2-3x+1x的值为______.-数学

题目简介

若x=30,那么xx-3-x+6x2-3x+1x的值为______.-数学

题目详情

若x=30,那么
x
x-3
-
x+6
x2-3x
+
1
x
的值为______.
题型:填空题难度:中档来源:不详

答案

class="stub"x
x-3
-class="stub"x+6
x2-3x
+class="stub"1
x

=class="stub"x
x-3
-class="stub"x+6
x(x-3)
+class="stub"1
x

=
x2
x(x-3)
-class="stub"x+6
x(x-3)
+class="stub"x-3
x(x-3)

=
x2-x-6+x-3
x(x-3)

=
x2-9
x(x-3)

=
(x+3)(x-3)
x(x-3)

=class="stub"x+3
x

当x=30时,原式=class="stub"30+3
30
=class="stub"11
10

故答案是:class="stub"11
10

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