Solving Equations with Elimination

Solve  the system of equations.  
   x + 5y = -27
-2x - 5y = 24

• (3, 6)

• (-3, -6)

• (-3, -4)

• (3, -6)

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

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

4x + 3y = 1

x - 3y = -11

• cross out the 3y and -3y

• cross out the 4x and x

• change all the signs of the second equation

• add 1 and -11

In this system of equations, what would be the first step?

5x + 7y = 77

5 x + 3y = 53

• Eliminate the x's

• Eliminate the y's

• Multiply the bottom row by -1 in order to eliminate the x's

• Multiply both rows by -1 in order to eliminate the x's

What would be the first step to solve this system?

• Multiply the bottom equation by -2 in order to eliminate the x's

• Multiply the bottom equation by 2 in order to eliminate the x's

• Multiply the bottom equation by 5 in order to eliminate the y's

• Be a baby bird and expect my teacher to spoon feed me

In order to eliminate.......

• The x's or the y's have to have the same coefficient, with the same sign

• The x's or the y's have to have the same coefficient, with opposite signs

• It doesn't matter, we can eliminate no matter what

• One of the x's or the y's has to be a bigger number than the other one.

In this system of equations, can we eliminate without having to change anything first?

7x + 2y = 10

-7x + y = -16

• yes

• no

If I solve a system of equations, and the answer at the end is 2 = 2, what is the solution?

• 2

• Infinite solutions

• No solution

• 0

Solve this system to find the y

-4x - 3y = -15

4x -7y = -15

• y = -3

• y = 7.5

• y = 3

• y= -7.5

Solve this system for both x and y

4x + 8y = 20

-4x + 2y = -30

• (-7, 1)

• (2, -5)

• (-2, 5)

• (7, -1)