Systems of equations by substitution

Multiple Choice

Given the system

y = 2x + 1

3x + y = -9

What should be substitute into the second equation for y?

WARNING - You need to write this down!

• 3x + y

• x

• -9

• 2x + 1

Multiple Choice

After substituting the expression in our new equation is____________.

• 3x + 2x + 1 = -9

• 2x + 3 = -9

• 3x + x = -9

• None of these.

Multiple Choice

Using the equation in question 3.

What is the value of x?

• x = 4

• x = -2

• x = -3

• x = -4

How did we get x?

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Multiple Choice

y = -2x + 18
y = 8

• (5, 8)

• (-5, 8)

• (2, 8)

• (-2, 8)

Multiple Choice

When solving this system of equations, how will the problem be set up to solve for the first variable?
 
5x + 4y= −14
y =  −7x  −  15 

• 5x + 4(-7x - 15) = -14

• 5(-7x - 15) 4y = -14

• -7x - 15 = -14

• 5x - 7x - 15 = -14

Multiple Choice

What is the next step?
 
5x + 4(-7x - 15) = -14

• add 5 + 4

• Distribute 4

• subtract -7-15

• move the 5 to the other side

Multiple Choice

Solve the system by substitution.
 
5x + 4y= −14
y =  −7x  −  15 

• (-2, -1)

• (1, -2)

• (-2, 1)

• (-1, -2)

Multiple Choice

When solving this system of equation, how will it be set up to solve by substitution?
y = 2x + 1
y = 4x - 1

• 2(4x - 1) + 1

• 2x + 1 = 4

• 2x + 1 = 4x - 1

• 4(2x + 1) - 1

Multiple Choice

Solve this system of equations. 
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Multiple Choice

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

Multiple Choice

The solution to a system of equations is any ordered pair that makes both equations true. 

• TRUE
• FALSE

Multiple Choice

What are the steps for graphing a line?

• 1. Plot y-intercept
  2. count slope ratio plot second point
  3. Draw the line.
• 1. Make a table
  2. Plot slope
  3. Draw line
• 1. Plot two points
  2. Check slope
  3. Draw line
• 1. Draw line
  2. Hope it is right

Multiple Choice

What kind of lines have no solution to a system of equations

• Parallell Lines
• Overlapping lines
• Intersecting Lines
• Skew Lines

Multiple Choice

^{What is the solution?} 

• 1
• -2
• (1, 2)
• (1, -1)

Math Response

Rewrite the bottom equation after using substitution. Do not solve the system.

Type answer here

Correct Answer: 4x-5\left(2x+1\right)=26

Deg^°

Rad

Match

Read each step of the Substitution method for solving a System of Equations. Then, match the result of performing the step with the step.

• Step 1: Solve one equation's variable (expression)

• Step 2: Substitute the expression in the other equation

• Step 3: Solve the equation for a value

• Step 4: Substitute the variable's value in the other equation; solve

• Step 5: Present the solution as an ordered pair

y = 5 - 2x

-3x + 6(5-2x) = 0

x = 2

2(2) + y = 5

y = 1

(2, 1)

• y = 5 - 2x

• -3x + 6(5-2x) = 0

• x = 2

• 2(2) + y = 5

  y = 1

• (2, 1)

Dropdown

Colleen was solving the following system of equations by substitution, but she thinks she made a mistake.

Did she? If so, help her fix it!



The mistake was: ​

Select answer

​

2x+5y=19

y=3x-3



Step 1: plug y=3x-3 in for y

2x+5(3x-3)=19

Step 2: Simplify and solve for x

2x+15x-3=19

17x-3=19

17x=22

x=22/17

Step 3: Plug x in and solve for y

y=3(22/17)-3

y=66/17-3

y=66/17-51/17

y=15/17