I am having lot of difficulty in solving data sufficiency problems involving equalities using algebraic manipulations.
I have below questions
1. Are all the Data sufficiency inequality problems that involve only one variable (say x) solvable if we set x to some set of values like 2,1,12,0, -1/2,-1,-2... depending on the constraints of the problem
2. When is it that algebraic manipulations are a must and above method will not work?
It does sound like you need to strength you understanding of concepts, especially algebra. I recommend posting specific questions in this forum and learning from the expert answers.
Here's a free lesson video you may find helpful about picking numbers on DS:http://gmat.magoosh.com/lessons/368-choosing-numbers
I hope that helps. Let me know if you have any further questions.
Magoosh Test Prep