题目内容
计算:
(1)x2y-
x2y-2x2y
(2)(3a-2)-3(a+5)
(3)(4a2b-5ab2)-(3a2b-4ab2)
(4)3x2-[7x-3(4x-3)-2x2].
(1)x2y-
| 2 |
| 5 |
(2)(3a-2)-3(a+5)
(3)(4a2b-5ab2)-(3a2b-4ab2)
(4)3x2-[7x-3(4x-3)-2x2].
(1)原式=(1-
-2)x2y
=-
x2y;
(2)原式=3a-2-3a-15
=-17;
(3)原式=4a2b-5ab2-3a2b+4ab2
=a2b-ab2;
(4)原式=3x2-[7x-12x+9-2x2]
=3x2-7x+12x-9+2x2
=5x2+5x-9.
| 2 |
| 5 |
=-
| 7 |
| 5 |
(2)原式=3a-2-3a-15
=-17;
(3)原式=4a2b-5ab2-3a2b+4ab2
=a2b-ab2;
(4)原式=3x2-[7x-12x+9-2x2]
=3x2-7x+12x-9+2x2
=5x2+5x-9.
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