问题
解答题
先化简，再求值：
|
答案
原式=
| 2(m-3) |
| (m+2)(m-2) |
| m(m-2)-4m+9 |
| m-2 |
=
| 2(m-3) |
| (m+2)(m-2) |
| (m-3)2 |
| m-2 |
=
| 2(m-3) |
| (m+2)(m-2) |
| m-2 |
| (m-3)2 |
=
| 2 |
| m2-m-6 |
∵m是方程2x2-2x-1=0的解，
∴2m2-2m-1=0，即m2-m=
| 1 |
| 2 |
∴原式=
| 2 | ||
|
| 4 |
| 11 |
搜题请搜索小程序“爱下问搜题”
先化简，再求值：
|
原式=
| 2(m-3) |
| (m+2)(m-2) |
| m(m-2)-4m+9 |
| m-2 |
=
| 2(m-3) |
| (m+2)(m-2) |
| (m-3)2 |
| m-2 |
=
| 2(m-3) |
| (m+2)(m-2) |
| m-2 |
| (m-3)2 |
=
| 2 |
| m2-m-6 |
∵m是方程2x2-2x-1=0的解，
∴2m2-2m-1=0，即m2-m=
| 1 |
| 2 |
∴原式=
| 2 | ||
|
| 4 |
| 11 |