x |
y |
2 |
7 |
x2-3xy+2y2 |
2x2-3xy+7y2 |
A.
| B.
| C.
| D.
|
x |
y |
2 |
7 |
2 |
7 |
x2-3xy+2y2 |
2x2-3xy+7y2 |
| ||||
|
60 |
309 |
20 |
103 |
2 |
a |
1 |
b |
2a+b |
a-b |
A.-5 | B.5 | C.-4 | D.4 |
5x |
x-2y |
A.缩小2倍 | B.缩小5倍 | C.缩小10倍 | D.不变 |
-a |
m-n |
A.
| B.
| C.
| D.-
|
x+y+z |
2x-y+z |
3-x |
-x2+7 |
x-3 |
( ) |
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