2a |
a+b |
A.是原来的20倍 | B.是原来的10倍 | ||
C.是原来的
| D.不变 |
2×10×a |
10a+10b |
10×2×a |
10(a+b) |
2a |
a+b |
x |
x+y |
A.扩大10倍 | B.缩小10倍 | C.扩大2倍 | D.不变 |
b |
a |
ab |
a() |
| ||
a+b |
() |
2a+2b |
3a+3b |
9c |
a+b |
() |
x |
3 |
y |
4 |
z |
5 |
xy+yz+zx |
x2+y2+z2 |
14xy(x+y)3 |
4x2(x+y)2 |
2x |
x+y |
A.扩大两倍 | B.不变 | C.缩小两倍 | D.不能确定 |
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