Substitution Methods

The solution (x, y) to a system of equations is the point where they...? 

• Run off the graph
• Don't touch
• Intersect
• Exist

What would you do first to solve the system of equations by substitution?

y = -4x + 5

y = 3x - 16

• Multiply

• Set the equations equal

• Solve for y

• Solve for x

What is the solution?

• (1, -1)
• (-1, 1)
• (0, -2)
• (0, 1)

What would you do first to solve the equations?

x - 2y = 2

3x + 4y = 3

• Set the equations equal

• Multiply

• Solve for x in one of the equations

• Substitute

This system has _____ solutions

• 0
• 1
• 2
• Infinitely many

What would you do first to solve the system of equations?

y = 3x - 8

y = 4 - x

• Set the equations equal

• Solve one of the equations for y

• Guess and check numbers for x

• Guess and check numbers for y

What is the first step in solving the following system of equations?

- 2x + y = -1

4x + 2y = 14

• Guess and check some numbers for y

• Set the equations equal

• Graph the equations

• Solve one equation for y

What is the solution?

• (1, -1)
• (-1, 1)
• (0, -2)
• (0, 1)

What is the first step in solving the following system of equations?

2x + y = 13

4x - 3y= 11

• Guess and check some numbers for y

• Graph the equations

• Set the equations equal

• Solve one equation for y

What would you do first to solve the equations?

y = 2x + 1

y = 4x - 1

• Solve for y

• Solve for x

• Set the equations equal

• Guess and check numbers