Substitution of Variables

What is the final 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

• Solve one equation for one of its variables

• Solve one equation for one of its variables

Solve the system by using the substitution method

• (3,6)

• (6,3)

• (1,4)

• (4,1)

Solve the system of equations using the substitution method

• (-2,6)

• (6,-2)

• (-2,4)

• (4,-2)

Solve this system by substitution.

• (1,-4)

• (1,4)

• (-4,-7)

• (-7,-4)

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

• 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 second 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

• 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 third 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

• 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 for x and y using the substitution method.

5x + 3y = 7

y = 4

• (4,1)

• (4,-1)

• (1,4)

• (-1,4)

AJ was asked to find the solution to this system of equations. x = 7 - 2y 2x + y = 5 Noticing that x was isolated and set equal to 7 - 2y, he decided to replace x in the second equation with its value. What method is AJ using and what equation did he write?

• Elimination; 2(7-2y) + y = 5

• Graphing; 2x = (7-2y) + y = 5

• Substitution; 2(7-2y) + y = 5

• Substitution; x = 7 - 2y + 2x + y = 5