what is |x| ?

1.what is |x| ?
X的絕對值

2.and what is this?
|a b c|
|d e f |
|g h i |
行列式
=aei+dhc+bfg-ceg-afh-bdi

3.|x|=x?
當x>=0時
|x|=x

4.give me question with |x| and the solution.
|x|=5, x=?
Answer: x=+-5

|x+2|=7, x=?

x+2=+-7
Answer: x=5,-9

|x| is the absoult value of x ,即係要把兩條線中間的x 無論係負定正 都要正!!

eg. I-5I=5 I-16I=16 I5I=5 I10I=10


so 如果x係正or 零 |x|=x 啦^^

For example, IxI=1
x=1 or -1 (因為 I-1I=1 and I1I = 1 )


IX+5I=6
x+5=6 or x+5=-6
x=1 or x=-11

hope the above can help you