Can anyone help me with these math problem?

Question

I have worked on these problems and found many examples but am still not getting the answer correctly. Can anyone help? Any explanations would be appreciated.
4/3+1/2=1/x
5/7y+4/y=1
2/x-2+7/x+2=-5x/x^2-4

Answer 1

 

The first step is to multiply both sides by the least common denominator.
For the first, multiply by 6x to get:
8x + 3x = 6
11x = 6
x = 6/11

For the second, multiply by 7y to get:
5 + 28 = 7y
33 = 7y
33/7 = y

For the last one, multiply by x^2 - 4 = (x+2)(x-2) to get:
2(x+2) + 7(x-2) = -5x
2x+4 + 7x-14 = -5x
9x-10 = -5x
-10 = -14x
10/14 or 5/7 = x