Answer:
To solve this system of equations using the substitution method, we need to isolate one of the variables in one of the equations and substitute its expression into the other equation.
From the first equation, we can see that y = 3x. We can substitute this expression for y in the second equation, like this:
3x + y = 30
3x + (3x) = 30 (substituting y = 3x)
6x = 30
x = 5
Now we can substitute this value of x back into either equation to find the value of y. We'll use the first equation:
y = 3x
y = 3(5)
y = 15
Therefore, the solution to the system of equations is (x, y) = (5, 15)