Algebra II Recipe: Solving Systems with Three Unknown Variables

1. Choose 2 different pairs of equations of the 3 given equations; for example: Eq1 and Eq2 paired with Eq1 and Eq3 OR Eq1 and Eq2 paired with Eq2 and Eq3
2. Use the multiplication-addition method to eliminate the same variable in each pair of equations.
3. Use the 2 resulting equations to eliminate one of the two remaining variables using the multiplication-addition method. This will result in finding the value of one of the variables.
4. Substitute the value found in step 3 into one of the equations with only two variables.
5. Now that you know the value of 2 variables, substitute these values into one of the equations with 3 variables to find the value of the third variable.
6. List the values in a set of parentheses in alphabetical order (x, y, z) for the answer.

1. Set up a matrix equation AX = B.
2. Enter matrix A and matrix B into the calculator.
3. Type A^-1· B into the calculator to get the answer.

Practice Problems