Question

Solve the system using elimination. 3 x plus 3 y equals 27. x minus 3 y equals negative 11.

Answer 1

Answer:

- 5/4

Step-by-step explanation:

Answer 2

Answer:

x=4 and y=5 commonly notated as (4,5)

Step-by-step explanation:

The equations

Equation 1: 3x+3y=27

Equation 2: x-3y= -11

The second equation looks like it will be the easiest to rearrange.

x-3y = -11

add 3y to each side to get

x = 3y-11

Substitute that in for x in equation 1 so

3x+3y=27

turns into

3(3y-11) +3y =27

multiply out to get

9y-33+3y =27

Condense variables

12y-33=27

add 33 to each side

12y= 60

Divide by 12

y = 5

Plug into one of the original equations (I will be doing both to show it doesn't matter what equation you use, but you only need to use one equation, I personally think it is easier to plug into the second equation)

Equation 1: 3x+3y=27

Plug in what we got for y

3x+3(5)=27

multiply

3x+15=27

subtract 15 from each side

3x=12

divide by 3

x=4

Equation 2: x-3y = -11

Plug in what we got for y

x-3(5) =-11

Multiply

x-15= -11

Add 15 to each side

x=4