Plug Into Equations

Put the steps for solving by SUBSTITUTION in order:

• Solve one equation for x or y

• Plug the resulting expression into the other equation

• Solve for the first variable

• Plug that number into the other equation

• Solve for the second variable

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

In this system x+3y=9 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

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

Consider the system:

4x+3y=-1

5x+4y=1

Since we now know that x=-7, solve for y:

4(​ (a)   )+3y=-1

​ (b)   +3y=-1

​ (c)   =​ (d)  

y=​ (e)  

• -7

• -28

• 3y

• 27

• 9

• 5

• 7

• -12

• 3

• y

What is the solution to the system of equations?

4x-y=3

3x+y=4

(​ (a)   ,​ (b)   )

• 1

• 2

• 3

• 4

• 5

• 6

• 7

• 8

• 9

• 0

Which ordered pair is the solution to this system?

HINT: plug the x number into the x in each equation and plug the y number into the y in each equation and solve to see which one works for BOTH!)

y = 2x + 1

y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Which ordered pair is the solution to this system?

HINT: plug the x number into the x in each equation and plug the y number into the y in each equation and solve to see which one works for BOTH!)

y = 2/3x - 2

y = -x + 3

• (0,3)

• (0,-3)

• (3,0)

• (-3,0)

Which ordered pair is the solution to this system?

HINT: plug the x number into the x in each equation and plug the y number into the y in each equation and solve to see which one works for BOTH!)

y = 1/2x + 2

y = -3x + 9

• (2,3)

• (-2,-3)

• (3, 2)

• (-3,2)

Please solve this equation

^p/₅ = 7

• p = 35

• p = 12

• p = 2

• None of these match my answer