x |
x-1 |
x2-9 |
x-3 |
x |
x-1 |
x2-9 |
x-3 |
n+1 |
n-1 |
A.1个 | B.2个 | C.3个 | D.4个 |
x-2 |
2x+1 |
A.x≠0 | B.x≠-
| C.x≠
| D.x≠2 |
2 |
x |
1 |
2x |
1 |
4 |
m-n |
5 |
5y2 |
2y |
A.①④⑥ | B.①②⑤ | C.③⑤ | D.①②④ |
x2-1 |
2(x+1) |
A.1 | B.±1 | C.0 | D.-1 |
x+y |
x2+y2 |
A.x、y不都为0 | B.x、y都不为0 | C.x、y都为0 | D.x=-y |
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