You can use substitution to find the solution.
Lets start by solving for m in the first equation.
w - 6 = m + 6 - 6 this leaves it as an equation of m
Now we can put this in place of m in the second equation.
w = 5(w - 6) - 10
w = 5w - 30 - 10
w = 5w - 40
w - 5w = -40
-4w = -40
-4w/-4 = -40/-4
w = 10
So now you put 10 in place of w.
10 - 6 = m + 6 - 6
4 = m
Mary is 4 and Wilson is 10
Put these in place of m and w in the other equation as well to double check.
10 + 10 = 5(4) - 10 + 10
20 = 20
So this is correct