Question

Y - (z + z); y = 10, z =2

Answer 1

Well in order to get the answer of this you have to plug in the values of numbers in the corresponding letters
E.J. 
10-(2+2), now solve for it to get 
10-(4) now subtract 4 from 10 to get 6

Hope this helps

Answer 2

The answer is 6. You just have to replace the values and done.