题目内容
先化简(1+| 5x-4 |
| x2-4x+4 |
| x+1 |
| x-2 |
分析:将1+
转化为
+
=
,最运用提取公因式、平方差公式将÷
转化为×
约去公因式化简.
| 5x-4 |
| x2-4x+4 |
| x2-4x+4 |
| x2-4x+4 |
| 5x-4 |
| x2-4x+4 |
| x2+x |
| x2-4x+4 |
| x+1 |
| x-2 |
| x-2 |
| x+1 |
约去公因式化简.
解答:解:原式=(
+
)÷
,
=
÷
,
=
•
,
=
.
当x=3时,原式=
=3.
说明:x的值不能取-1及2.
| x2-4x+4 |
| x2-4x+4 |
| 5x-4 |
| x2-4x+4 |
| x+1 |
| x-2 |
=
| x2+x |
| x2-4x+4 |
| x+1 |
| x-2 |
=
| x(x+1) |
| (x-2)2 |
| x-2 |
| x+1 |
=
| x |
| x-2 |
当x=3时,原式=
| 3 |
| 3-2 |
说明:x的值不能取-1及2.
点评:在通分中往往将“1”转化为分式的形式.如本题中的“1”用“
”这种形式来代替,最终达到化简的目的.
| x2-4x+4 |
| x2-4x+4 |
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