Solving Systems of Equations by Substitution

The video tutorial covers solving systems of equations using the substitution method. It begins with an introduction to the concept, comparing it to graphing, and explains why substitution is more precise. The tutorial includes detailed examples, demonstrating how to substitute variables to find exact solutions. It concludes with a real-world word problem, illustrating the practical application of these techniques.

What is the main advantage of using substitution over graphing when solving systems of equations?

• It is easier to understand.

• It always provides an exact answer.

• It is faster.

• It requires less calculation.

In the example where y = 3x and x + y = -32, what is the value of x?

• -4

• -8

• 4

• 8

After finding x = -8 in the previous example, what is the value of y?

• 24

• -8

• -24

• 8

When both equations equal y, what should you do to find the solution?

• Subtract one equation from the other.

• Add the equations together.

• Multiply the equations.

• Set the equations equal to each other.

In the example where y = 2x + 7 and y = x - 1, what is the value of x?

• -1

• 1

• -8

• 8

In the example where y = 2x + 7 and y = x - 1, what is the value of y?

• -7

• 7

• 9

• -9

What is the first step in solving a system of equations by isolating a variable?

• Add the equations together.

• Isolate the variable with a coefficient of 1.

• Multiply the equations.

• Subtract one equation from the other.

In the example where x = -3y - 7, what is the value of y?

• 9/43

• 43/9

• -43/9

• -9/43

In the snack pack word problem, how many large snack packs were sold?

• 20

• 40

• 60

• 80

In the snack pack word problem, how many small snack packs were sold?

• 60

• 40

• 80

• 20