计算:①2a+3a=______,②ba-cb=______,③(-3b2a)2=______,④1x-1y=______,⑤2aa-b+a+bb-a=______⑥x2-1(x+1)2=()x+1;

题目简介

计算:①2a+3a=______,②ba-cb=______,③(-3b2a)2=______,④1x-1y=______,⑤2aa-b+a+bb-a=______⑥x2-1(x+1)2=()x+1;

题目详情

计算:①
2
a
+
3
a
=______,②
b
a
-
c
b
=______,③(-
3b
2a
2=______,④
1
x
-
1
y
=______,⑤
2a
a-b
+
a+b
b-a
=______⑥
x2-1
(x+1)2
=
()
x+1
;______,⑦
a2
a+3
-
9
a+3
=______;⑧
a
a-b
+
b
b-a
=______.
题型:填空题难度:中档来源:不详

答案

class="stub"2
a
+class="stub"3
a
=class="stub"5
a

class="stub"b
a
-class="stub"c
b
=
b2-ac
ab

③(-class="stub"3b
2a
)2=
9b2
4a2

class="stub"1
x
-class="stub"1
y
=class="stub"y-x
xy

class="stub"2a
a-b
+class="stub"a+b
b-a
=class="stub"2a-a-b
a-b
=class="stub"a-b
a-b
=1;
x2-1
(x+1)2
=
(x+1)(x-1)
(x+1)2
=class="stub"x-1
x+1

a2
a+3
-class="stub"9
a+3
=
a2-9
a+3
=
(a+3)(a-3)
a+3
=a-3;
class="stub"a
a-b
+class="stub"b
b-a
=class="stub"a
a-b
-class="stub"b
a-b
=class="stub"a-b
a-b
=1.
故答案是:class="stub"5
a
b2-ac
ab
9b2
4a2
class="stub"y-x
xy
class="stub"x-1
x+1
,1,a-3,1.

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