Systems of Equations Using the Elimination Method

Solve the following system by using elimination:

-9x - 2y = -23

-10x - 5y = -20

• (-3, -2)

• (3, 2)

• (3, -2)

Solve the following system by using elimination:

3x + 3y = 0

7x + 5y = -16

• (8, 4)

• (-8, 8)

• (-8, -8)

• Add the x terms in the two equations and the y terms in the two equations so you get 3x + 8y = 11

• Multiply all terms in the top equation by 2 so that you  can eliminate the x terms

• Multiply the x in the first equation by -2 so you get -2x + y = 2

• Multiply all terms in the top equation by -2 so that you can eliminate the x terms. 

What would be the first step in finding the solution with elimination?

• cross out the 3y and -3y

• cross out the 4x and x

• change all the signs of the second equation

• add 1 and -11

What would be the first step in finding the solution using elimination?

2x + 2y = -2

3x - 2y = 12

• you cannot solve this using eliminiation

• cross out the 2x and 3x

• cross out the 2y and -2y

• change to slope intercept form and graph

The first step in using the Elimination Method to solve a system of equations is to

• get both equations in slope-intercept form.

• look for a zero pair.

• get the x term or y term isolated.

• identify the m and the b of the equation.

• Multiply the entire first equation by 2

• Multiply the entire first equation by -2

• Multiply the entire second equation by -1

• Multiple the entire first equation by 7

Solve the system by elimination.

7x - y = -10

-7x + 5y = -6

• (-2, -4)

• (-2, -1)

• (-4, -1)

• (6, -8)

a method to solving a system of equations by getting rid of one of the variables first to solve for the other variable. 

• Systems by Graphing

• Systems by Substitution

• Systems by Elimination

• Systems by Drawing

Alexandra finds that she can give 3 haircuts and 2 hair dyes in 315 minutes. Giving 2 haircuts and 4 hair dyes takes 450 minutes.  Which system of equations represents the situation?

• 3x + 2y = 315
  2x + 4y = 450

• 3x + 2y = 450
  2x + 4y = 315

• 2x + 2y = 315
  3x + 4y = 450