问题
解答题
(1)先化简再求值 (x-1-
(2)计算:
|
答案
(1) (x-1-
)÷8 x+1 x+3 x+1
=
•x2-9 x+1 x+1 x+3
=x-3.
把x=3-
代入,上式=3-2
-3=-2
.2
(2)
+(-5)2
-2
+13
+(--20 0.2
)-13 3
=5+
-1+5-3 3
=9.
(1)先化简再求值 (x-1-
(2)计算:
|
(1) (x-1-
)÷8 x+1 x+3 x+1
=
•x2-9 x+1 x+1 x+3
=x-3.
把x=3-
代入,上式=3-2
-3=-2
.2
(2)
+(-5)2
-2
+13
+(--20 0.2
)-13 3
=5+
-1+5-3 3
=9.