问题
解答题
(1)计算:(-1)2011+3×
(2)先化简,再求值:(
|
答案
(1)(-1)2011+3×
1 | ||
|
3 |
=-1+
3 |
3 |
=1;
(2)(
3x |
x-1 |
x |
x+1 |
x2-1 |
x |
=
x(3x+3-x+1) |
(x+1)(x-1) |
(x+1)(x-1) |
x |
=2x+4,
把x=
2 |
原式=2x+4=2
2 |
2 |
(1)计算:(-1)2011+3×
(2)先化简,再求值:(
|
(1)(-1)2011+3×
1 | ||
|
3 |
=-1+
3 |
3 |
=1;
(2)(
3x |
x-1 |
x |
x+1 |
x2-1 |
x |
=
x(3x+3-x+1) |
(x+1)(x-1) |
(x+1)(x-1) |
x |
=2x+4,
把x=
2 |
原式=2x+4=2
2 |
2 |