Solving Systems of Equations by Elimination

What is the primary focus of this lesson?

• Solving systems by graphing

• Solving systems by factoring

• Solving systems by substitution

• Solving systems by elimination

Which method works well when both variables are on the same side of the equation?

• Graphing

• Factoring

• Substitution

• Elimination

What does the addition property of equality state?

• Divisions of equals are equal

• Multiples of equals are equal

• Equals subtracted from equals are equal

• Equals added to equals are equal

What happens when you add two equations together and one variable cancels out?

• You eliminate one variable

• You graph the equations

• You solve for both variables

• You get a new system of equations

In the example, what is the result of adding X + Y = 21 and X - Y = 9?

• X = 15

• 2X = 30

• Y = 6

• 2Y = 30

What should you do if there are no additive opposites in the system?

• Use graphing method

• Use substitution method

• Solve by factoring

• Create opposites using multiplication

What is the multiplicative property of equality?

• You can divide both sides of an equation by the same number

• You can multiply both sides of an equation by the same number

• You can subtract the same number from both sides of an equation

• You can add the same number to both sides of an equation

In the final example, what do you multiply the second equation by to create additive opposites?

• 3

• 5

• 4

• 2

What is the solution to the system 2x + y = 20 and 3x - 2y = -12 after using elimination?

• x = 5, y = 3

• x = 4, y = 12

• x = 6, y = 1

• x = 8, y = 2

What is the final step to ensure the solution is correct?

• Graph the equations

• Check the solution in the original equations

• Multiply both sides by a constant

• Subtract the equations