题目内容
计算:
(1)(-2ab+3a)-(2a-b)+6ab;
(2)(3x2y3)2÷(-
x4y2);
(3)先化简,再求值:(x+2)2-(x+3)(x-3),其中x=-2.
(1)(-2ab+3a)-(2a-b)+6ab;
(2)(3x2y3)2÷(-
| 1 |
| 3 |
(3)先化简,再求值:(x+2)2-(x+3)(x-3),其中x=-2.
(1)(-2ab+3a)-(2a-b)+6ab
=-2ab+3a-2a+b+6ab
=4ab+a+b;
(2)(3x2y3)2÷(-
x4y2)
=9x4y6÷(-
x4y2)
=-27y4;
(3)(x+2)2-(x+3)(x-3)
=x2+4x+4-x2+9
=4x+13
当x=-2时,原式=-8+13=5.
=-2ab+3a-2a+b+6ab
=4ab+a+b;
(2)(3x2y3)2÷(-
| 1 |
| 3 |
=9x4y6÷(-
| 1 |
| 3 |
=-27y4;
(3)(x+2)2-(x+3)(x-3)
=x2+4x+4-x2+9
=4x+13
当x=-2时,原式=-8+13=5.
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