问题
解答题
计算: (1)-
(2)(x4+2x3-
(3)化简求值:(a2+b2)(a2-b2)-(a+b)2(a-b)2,其中a=4,b=1. |
答案
(1)原式=-
+1 4
+(1 4
-3
)-(2
-3
)+2=2;2
(2)原式=x4÷(
x2)+2x3÷(1 4
x2)-1 4
x2÷(1 2
x2)=4x2+8x-2;1 4
(3)原式=(a2-b2)(a2+b2)-(a2-b2)2,
=(a2-b2)(a2+b2-a2+b2),
=(a2-b2)•2b2,
=(16-1)×2,
=30.