Solving Systems by Elimination Advanced

Erin is 3 years younger than twice Alex's age. Their ages combined are 33 years. How old are Alex and Erin. If x=Erin's age and y=Alex's age, choose the system that matches the situation.

• x + y = 33
  y = 2x - 3

• x + y = 33
  x = 2y - 3

• x + y = 33
  x = 3 - 2y

• x + y = 3
  x = 33 - 2y

What would be the first step to solve this system by elimination?

2x+9y= -7

6x-3y= 9

• Add the equations

• Subtract the equations

• Write each equation in slope intercept form.

• Multiple the first equation by 3 or -3

Which strategy is the best choice for solving this system?

4x − 4y = 10

4x + 4y = 0

• Elimination

• Making trials

• Substitution

• Graphing

Which variable will be eliminated first?

• x

• y

If a system of linear equations has infinitely many solutions, what does this mean about the two lines? 

• Intersecting lines

• Same line

• Parallel lines

The talent show committee sold a total of 530 tickets in advance. Student tickets cost $3 each and the adult tickets cost $4 each. If the total receipts were $1740, how many of each type of ticket were sold? What of the following systems represent this situation?

• S + A = 530

  3S + 4A = 1740

• S + A = 530

  4S + 3A = 1740

• S + A = 1740

  3S + 4A = 530

• S + A = 1740

  4S + 3A = 530

Which method would be best (quickest) for solving the system below:

x + y = 11

3x - 4y = -2

• Making trials

• Elimination

• Graphing

• None of these

________________ are two or more equations that have the same variables and work together.

• graphing lines

• elimination method

• system of equations

• table

Solve by elimination:
-x+2y=17

2x+2y=-10

• ARN

• (-9,4)

• (-9,-4)

• (9,-4)

Solve by elimination

4x-6y= -6

-2x-12y= -12

• (0,1)

• (1,0)

• (1,1)

• (0, 2)