问题
解答题
计算题: (1)(
(2)|
(3)(x+1)(x-5)+4(x-1) (4)(a+b-c)(a-b+c) |
答案
(1)原式=3-4-2+2
=-1;
(2)原式=
-3
-(2-2
)-(3
-1)3
=
-3
-2+2
-3
+13
=
-3 2
-1;
(3)原式=x2-5x+x-5+4x-4
=x2-9;
(4)原式=[a+(b-c)][a-(b-c)]
=a2-(b-c)2
=a2-(b2-2bc+c2)
=a2-b2+2bc-c2.