Solving Systems of Equations by Substitution

The video tutorial covers solving systems of equations by substitution without using graphs or calculators. It begins with an introduction to the substitution method, followed by a detailed explanation of the steps involved. Three examples are provided to demonstrate the process, each illustrating how to isolate variables, substitute expressions, and solve for the remaining variables. The tutorial concludes with a summary of the method and encourages students to practice the skills learned.

What is the first step in solving systems of equations by substitution?

• Substitute the expression into the variable of the other equation

• Isolate the variable in one of the equations

• Solve for the remaining variable

• Write the solution as an ordered pair

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CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In the first example, which variable is easiest to isolate in the second equation?

• 4y

• 3x

• y

• x

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CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

After isolating y in the first example, what is the new form of the second equation?

• y = -2x - 9

• y = 2x - 9

• y = -2x + 9

• y = 2x + 9

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CCSS.8.EE.B.6

CCSS.8.F.A.3

What is the value of x in the first example after solving the substituted equation?

• 5

• 3

• 4

• 2

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CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the final solution as an ordered pair for the first example?

• (4, 1)

• (3, 2)

• (1, 4)

• (2, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In the second example, which equation is easier to isolate a variable?

• Both are equally easy

• Equation 1

• Neither

• Equation 2

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CCSS.7.EE.B.4A

What is the value of y in the second example after solving the substituted equation?

• -2

• 3

• 2

• -3

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

What is the final solution as an ordered pair for the second example?

• (3, 2)

• (-3, -2)

• (-2, -3)

• (2, 3)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In the third example, which equation already has the variable isolated?

• Both

• Equation 2

• Equation 1

• Neither

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CCSS.6.EE.B.7

What is the final solution as an ordered pair for the third example?

• (-3, 4)

• (4, -3)

• (-4, 3)

• (3, -4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6