Solve and check each of the following.

1. 2x/7 + 3x/2 = 25/7

2. x-2/2 - x+2/4 = 1/2

3. 2.4x - 1.2x = 4.8

Please explain to me how to find the answers to these questions. My teacher is giving me a test on problems like these and I'm trying to study for it but I need help in understanding these problems. Any help is appreciated.