
Parviz F. answered 04/26/14
Tutor
4.8
(4)
Mathematics professor at Community Colleges
And is necessary , and or is sufficient condition.
Like if:
l X l < 7
- 7 < X < 7 -7---------+7
Solution of X in addition to be less than +7 has to be greater than -7 at the same time.(and)
However:
l X l > 7
X > 7 or X < -7 --------- -7 +7 -----------
Here either X =-8 or X = +8 are sufficient to be the solution.