题目内容
计算:①-2x2(
xy+y2)
②(2x-y)(2x+y)-(x-3y)2
| 1 |
| 2 |
②(2x-y)(2x+y)-(x-3y)2
①原式=-x3y-2x2y2;
②原式=4x2-y2-(x2-6xy+9y2),
=4x2-y2-x2+6xy-9y2,
=3x2+6xy-10y2.
②原式=4x2-y2-(x2-6xy+9y2),
=4x2-y2-x2+6xy-9y2,
=3x2+6xy-10y2.
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