Solving Systems of Equations by Substitution

What is the first step to solve a system with substitution?

• Substitute the values found from the previous step into one of the original equations and solve for the remaining variable

• Solve the linear system for both its variables

• Isolate one of the variables to get slope/intercept form of the equation

• Substitute the expression from the previous step in the other two equations to obtain a linear system in two variables

What is the second step to solve a system with substitution?

• Substitute the value found from the previous step into the other equation

• Solve the linear system for both its variables

• Solve one equation for one of its variables

• Substitute the expression from the previous step into both original equations to obtain a linear system in two variables

What is the third step to solve a system with substitution?

• Solve the equation from the previous step to find the value of the first variable

• Solve the linear system for both its variables

• Solve one equation for one of its variables

• Substitute the expression from the previous step in the other two equations to obtain a linear system in two variables

What is the final step to solve a system with substitution?

• Substitute the value found from the previous step into one of the original equations and solve for the remaining variable

• Solve the linear system for both its variables

• Solve one equation for one of its variables

• Substitute the expression from the previous step in the other two equations to obtain a linear system in two variables

Solve by Substitution:

y = -6

-3x - 6y = 24

• (6, 6)

• (6, -6)

• (4, -6)

• (-6, 4)

Solve the following systems of equations using substitution:

x = 6

y = 2x - 3

• (6, 6)

• (6, 9)

• (9, 6)

• (9, 9)

Solve the following systems of equations using substitution:

2y + x = -15

x = 3y

• (-3, -9)

• (-9, -3)

• (-3, 9)

• (9, -3)

Which graph represents a system of equations with infinite solutions?

• 
• 
• 
• None of the above

Solve:
3x + 2y = 16
7x + y = 19

• (-2,5)
• (-2,-5)
• (2,-5)
• (2,5)

y = 6x - 11

-2x - 3y = -7