Solving Systems by Substitution Steps

Which option shows the CORRECT substitution for this system?

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which option shows the CORRECT substitution for this system?

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which option shows the CORRECT substitution for this system?

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Which option shows the CORRECT substitution for this system?

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• Infinite number of solutions

• (0, 7)

• (-5, -7)

• (5, 7)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Put the steps for solving by SUBSTITUTION in order:

• Solve for the second variable

• Plug that number into the other equation

• Plug the resulting expression into the other equation

• Solve for the first variable

• Solve one equation for x or y

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In this system

x+3y=9

4x-2y=-6

it'll be easiest to start by solving the first equation for x.

The result of doing so is x=​9-3y.

Fill in the blanks to plug that expression in and solve for y:

4(​9-3y)-2​y =-6

36-​12y-2y=​-6

36-​14y =-6

-14y=​ (a)  

y=​ (b)  

• -42

• 3

• 30

• -3

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In this system

x+3y=9

4x-2y=-6

it'll be easiest to start by solving the first equation for x.

The result of doing so is x=​

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In this system

x+3y=9

4x-2y=-6

it'll be easiest to start by solving the first equation for x.

The result of doing so is x=​9-3y.

Fill in the blanks to plug that expression in and solve for y:

4(​ (a)   )-2​ (b)   =-6

36-​ (c)   y-2y=​ (d)  

36-​ (e)   =-6

• 9-3y

• y

• 12

• -6

• 14y

• x

• 10y

• x+3y

• 24y

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

In this system

x+3y=9

4x-2y=-6

we have figured out that x=9-3y, and y=3.

Complete the steps to solve for x:

x=9-3(​ (a)   )

x=9-​ (b)  

x=​ (c)  

The solution to the system is (​ (d)   ,​ (e)   ).

• 3

• 9

• 0

• y

• x

• y=3

• 3y

• -9

• 18

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6