Add/Subtract Elimination

7x - y = 10

-7x + y = -14

• No Solution

• (4, 1)

• Infinitely Many Solutions

• (2, -4)

Answer explanation

7x - y = 10

-7x + y = -14

All of the like terms have opposite coefficients, so both variables will be eliminated when we add the equations together. We cannot eliminate one without the other.

We are left with:

0=-4

This is a contradiction (false), so there is NO SOLUTION.

Solve the following using elimination. x-y=11 2x+y=19

• (10,-1)

• (-1,10)

• (-1,-10)

• (-10,-1)

Answer explanation

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 4

• Multiply one equation by 5

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 4

• Multiply one equation by 2

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 5

• Multiply one equation by 7

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 8

• Multiply one equation by 2

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 3

• Multiply one equation by 5

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 2

• Multiply one equation by 5

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 2

• Multiply one equation by 8

In order to solve this system by elimination, what should your first step be?

• Add the system

• Subtract the system

• Multiply one equation by 6

• Multiply one equation by 3