Solve the following system of equations by substitution: x - 4y = -12 and 3x + 2y = -8

Answer 1

Answer 2

1. Solve one of the equations for either x or y.

2. Substitute the equation from step 1 into the 

    other equation. (You will be substituting an 

    equation into an equation).

3. Solve the new equation. It will only have 1 variable.

4. Once you have a value for one of the variables, 

    substitute it into the equation from step 1 and 

    solve.

5. Now you have solved for x and y so this is your 

    solution. 

6. Check your solution in both equations.

Step 1: Since x has a coefficient of 1 in the 

             first equation … x = 4y - 12

Step 2:  3(4y - 12) + 2y = -8

Step 3:  12y - 36 + 2y = -8

                14y - 36 = -8

                 14y = 28

                     y = 2

Step 4: x = 4(2) - 12

               x = 8 - 12

               x = -4   



Step 5: Solution (-4,2)