The method of substitution is when one solves an equation for one of the variables, and then substitutes the expression into the other equation. After doing so, one will solve the other equation for the remaining variable and then backsolve for the first variable.
4x + 2y = 12
x = y + 3
The second equation is already sovled for parameter (x), subttiute this into the other equation,
4(y + 3) + 2y = 12
Distribute,
4y + 12 + 2y = 12
Simplify,
6y + 12 = 12
Inverse operations,
6y + 12 = 12
-12
6y = 0
/6
y = 0
Backsolve for (x), substitute the value of (y) into the equation for (x) and solve,
