Solve the system of equations by substitution.

Substituting the value of y from the second equation into the first equation, we have:

x + 5x = 12

6x = 12

x = 12/6

x = 2

Substituting this value back into the second equation to find the value of y:

y = 5(2)

y = 10

Therefore, the solution to the system of equations is (2, 10).