问题
解答题
(1)计算:(-1)2012-|1-6tan30°|-(-
(2)求不等式组
(3)先化简,再求值:(
|
答案
(1)原式=1-|1-6×
|-1+23 3 3
=1-(2
-1)-1+23 3
=1-2
+1-1+23 3
=1;
(2)
,x-3(x-2)≥4…①
<1-x…②1-2x 4
解①得:x≤1,
解②得:x<
,3 2
则不等式组的解集是:x≤1,
则非负整数解是:0和1.
(3)原式=
•(x+1)(x-1)-x(x-2) x(x+1) (x+1)2 x(2x-1)
=
•2x-1 x(x-1) (x+1)2 x(2x-1)
=
,x+1 x2
∵x2-x-1=0,
∴x2=x+1,
∴原式=1.