Solving systems of linear equations by substitution

Solving systems of linear equations by substitution

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Substitution method

A method of solving the system of linear equations by substituting equations within one another

Steps:

• Solve one equation for x (x=....) or or y (y=...)

• Substitute x = ... or y = ... from the first step into the other equation and solve for the variable

• Substitute your answer into the revised equation from Step 1 and solve for the second variable.

Substitute 6x into the second equation 2x+3y=-20

Multiple Choice

 $y\ =\ 3x$  

 $y=4x+3$  

After substituting the first equation into the second, I will get:

• 3x

•  $3x=4x+3$  

• I need help on this one

• 4x+3

Multiple Choice

 $y\ =\ 7x-3$  

 $x+3y=9$  

After substituting the first equation into the second, I will get:

• 7x-3=9

•  $x+3\left(7x-3\right)=9$  

• 10x

• I need. help on this one

Multiple Choice

 $x\ =\ 5y$  

 $2x+y=14$  

After substituting the first equation into the second, I will get:

•  $2\left(5y\right)+y\ =\ 14$  
  

•  $2x+x=14$  

• 5y+y=14

• I need. help on this one

Multiple Choice

 $y\ =\ 5x-5$  

 $y=14x$  

After substituting the first equation into the second, I will get:

•  $y\ =\ 5x-5+14x$  
  

•  $y=14x$  

•  $5x-5=14x$  

• I need. help on this one

Open Ended

Solve an equation for x (Find x)

1. Use dustributive property

2. Combine Like terms

3. Undo addition subtraction

4 Undo multiplication/division

Open Ended

Solve an equation for y, find y

Open Ended

The final answer is: