Solving Systems by Substitution

What is the final step in solving a system of equations by substitution?

• Divide the equations by a common divisor

• Multiply the equations by a common multiple

• Substitute the value found back into one of the original equations to solve for the other variable

• Add the equations together

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In the system of equations x - y = 3 and 2x + y = 7, what is the value of x when using the substitution method?

• 10

• 0

• 2

• 5

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In the system of equations 3x - 2y = 8 and 4x + y = 10, what is the value of y when using the substitution method?

• 2

• 4

• 6

• 10

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

When is it most beneficial to use the substitution method over other methods of solving systems of equations?

• When the system has only one equation

• When one of the equations can be easily solved for one variable

• When both equations are complex

• When the variables cannot be isolated

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system of equations using substitution:
y = 2x + 5
2x + 2y = 4

• (1, 7)

• (7, 1)

• (2, 9)

• (-1, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

The solution (x, y) to a system of equations is the set of numbers that make ...?

• All equations false

• At least one equation true

• All equations true

• At least one equation false

Tags

CCSS.8.EE.C.8B

If the solution is infinitely many the lines will ________?

• intersect at exactly one point

• be parallel

• overlap each other

• never exist

Tags

CCSS.8.EE.C.8A

The first step in solving using the substitution method is __________.

• get x by itself

• get y by itself

• get either variable by itself

• add the equations together

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve the system by substitution. 
-5x - 4y = -9
y = 6

• (3, 6)

• (6, -3)

• (-3, 6)

• (6.8, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In 3x + 2y = 10    and    x - 5y = 18, which variable should you isolate first?

• The x in the first equation

• The y in the first equation

• The x in the first equation

• The x in the second equation

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6