题目内容
(1)计算:|
-2|+
+
;
(2)分解因式:(p-4)(p+1)+3p;
(3)先化简,再求值:[(x+y)2-y(2x+y)-8x]÷2x,其中x=-2.
| 3 |
| 3 | -8 |
| (-2)2 |
(2)分解因式:(p-4)(p+1)+3p;
(3)先化简,再求值:[(x+y)2-y(2x+y)-8x]÷2x,其中x=-2.
(1)原式=2-
-2+2
=2-
;
(2)原式=p2+p-4p-4+3p
=p2-4
=(p+2)(p-2);
(3)[(x+y)2-y(2x+y)-8x]÷2x
=[x2+2xy+y2-2xy-y2-8x]÷2x
=[x2-8x]÷2x
=
x-4,
当x=-2时,原式=
×(-2)-4=-5.
| 3 |
=2-
| 3 |
(2)原式=p2+p-4p-4+3p
=p2-4
=(p+2)(p-2);
(3)[(x+y)2-y(2x+y)-8x]÷2x
=[x2+2xy+y2-2xy-y2-8x]÷2x
=[x2-8x]÷2x
=
| 1 |
| 2 |
当x=-2时,原式=
| 1 |
| 2 |
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