题目内容
计算或化简
(1)计算:(-1)2013-(
-
)0+(
)-1
(2)化简:(
-
)÷
(3)化简:(1-
)÷
(4)先化简(
+
)÷
,然后选取一个合适的整数a代入求值,其中-2≤a≤2.
(1)计算:(-1)2013-(
3 |
2 |
1 |
2 |
(2)化简:(
x2 |
x+4 |
16 |
x+4 |
x-4 |
x |
(3)化简:(1-
1 |
a-1 |
a2-4a+4 |
a2-a |
(4)先化简(
a |
a+2 |
2 |
a-2 |
1 |
a2-4 |
(1)原式=-1-1+2
=0;
(2)原式=
÷
=(x-4)×
=x;
(3)原式=
÷
=
×
=
;
(4)原式=
×(a+2)(a-2)
=a(a-2)+2(a+2)
=a2-2a+2a+4
=a2+4,
当a=1时,原式=1+4=5.
=0;
(2)原式=
(x+4)(x-4) |
x+4 |
x-4 |
x |
=(x-4)×
x |
x-4 |
=x;
(3)原式=
a-2 |
a-1 |
(a-2)2 |
a(a-1) |
=
a-2 |
a-1 |
a(a-1) |
(a-2)2 |
=
a |
a-2 |
(4)原式=
a(a-2)+2(a+2) |
(a+2)(a-2) |
=a(a-2)+2(a+2)
=a2-2a+2a+4
=a2+4,
当a=1时,原式=1+4=5.
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