The question may be incomplete but I think I get the gist of the problem you are asking. Since there are two independent equations given, then there are two unknown, this system is solvable. So, I think you are trying to find the values of the two unknowns, w and z.
2w-5z=13 ---> eq 1
6w+3z=10 ---> eq 2
In order to solve this simultaneously, let's rearrange eq 2 in terms of z, then substitute it to the first equation:
3z = 10 - 6w
z = 10/3 - 2w --> eq 3
2w-5z=13
2w - 5(10/3 - 2w) = 13
2w - 50/3 + 10w = 13
12w = 13 + 50/3
12w = 89/3
w = (89/3)/12
w = 89/36 or 2.472
Substituting w to eq 3:
z = 10/3 - 2(89/36)
z = -29/18 or -1.611
