Very simple inequation: 2 - x < 3 How to solve it?The solutions tells me its S = ]-1, +, but I can't get there I hate Maths, and I haven't had an exam with Inequations in a long time

Expert Answers
pohnpei397 eNotes educator| Certified Educator

I do not know what you are getting as your answer, but I wonder if you might be forgetting to switch the inequality sign.  Lots of people make that mistake.

To do this equation, start as if it were an equality.  In other words, subtract 2 from both sides to leave only x on one side.

Now you have -x < 1

To make x positive, multiply both sides by -1.  When you do this, you must switch the direction of the inequality sign.

So now x > -1

So this means that the solution is -1 or any number higher than that.

neela | Student

To solve 2-x<3.


We solve an equation or an iequality of one variable by adding or subtracting equals with a purpose of keeping varible or unknons one side and the knowns or numbers on the other sides.

2-x<3. Add x to both sides.

2-x+x<3+x. Simplify both sides. 2<3+x.

Now subtract 3 from both sides and we get: 2-3 < 3+X-3. Simplify. We get:


That means x is any number greater than -1 but not equal to -1 . This is written in an open interval notation like:

[-1 , + ifinity [  ,  as the end points are not contained in the interval.