题目内容
计算:
(1) (-2)2+(-3)0+3-1
(2)计算:(3x+2)+2(x2-x+2)
(3)(3a5b3-2a4b5)÷(-ab)3
(4)先化简,再求值:(a+b)(a-b)+(a+b)2-2a2,其中a=3,b=-
.
(1) (-2)2+(-3)0+3-1
(2)计算:(3x+2)+2(x2-x+2)
(3)(3a5b3-2a4b5)÷(-ab)3
(4)先化简,再求值:(a+b)(a-b)+(a+b)2-2a2,其中a=3,b=-
| 1 |
| 3 |
(1)原式=4+1+
=5
.
(2)原式=3x+2+2x2-2x+4=2x2+x+6.
(3)原式=
=
=-3a2+2ab2
(4)原式=a2-b2+a2+2ab+b2-2a2=2ab;当a=3,b=-
时,原式=-2.
| 1 |
| 3 |
| 1 |
| 3 |
(2)原式=3x+2+2x2-2x+4=2x2+x+6.
(3)原式=
| 3a5b3-2a4b5 |
| (-ab)3 |
| (ab)3(3a2-2ab2) |
| -(ab)3 |
(4)原式=a2-b2+a2+2ab+b2-2a2=2ab;当a=3,b=-
| 1 |
| 3 |
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