I want to find voltage across 5 ohm resistance by thevenins theorem
A rather faster way to do it, practically in ones head, is to notice that all the supplies are in parallel. So convert them all to their Norton equivalent.

By inspection, the first source is 10A//2ohms, the second is -10A/1ohm, and the third source 3A//4ohms. 

That's a total current into node A of 3A, with a total shunt resistance of 2//1//5//4 (OK, I used the calculator for that bit!) which is a resistance of 0.5128 ohms, which at 3A is 1.538v.

It's always nice to do a problem using several different methods and get the same answer.

Confession, my first answer was 11.79v. I wonder how many other people didn't notice the 10v source was reversed compared to the other two!