Algebra I Recipe: Solving Systems of Linear Equations Using the Multiplication-Addition Method
1. Multiply one or both of the equations by some number so that one of the variables will have opposites as coefficients.
2. Add the equations to eliminate the variable having opposites as coefficients.
3. Solve the remaining equation for its variable.
4. Substitute the value found in step 3 into either one of the original equations to find the value of the other variable.
5. When adding the equations in step 2 – if both variables cancel:
• The answer is IMS, if a true statement remains.
• The answer is NO SOLUTION, if a false statement remains.
Examples:
 2x - 4y = 134x - 5y = 8
 7x - 12y = -22-3x + 8y = 18
Real Life: A caterer is planning a party for 75 people. The customer has \$170 to spend. A \$35 pan of lasagna feeds 12 people and a \$10 cheese and crackers tray feeds 9 people. How many pans of lasagna and how many cheese and crackers trays should the caterer make?
 People per pan * Pans of lasagna + People per tray * Trays of cheese and crackers = People at the party Price per pan * Pans of lasagna + Price per tray * Trays of cheese and crackers = Money to spend on food Translate the problem into relationships and variables. In this case, let x equal the number of pans of lasagna and y equal the number of cheese and crackers trays12x +   9y =   7535x + 10y = 170

G Redden

Show Related AlgebraLab Documents