Student Question

Solve this linear equation using the elimination method.

1/2x+2y=27,x+1/3y=10

 X=? and Y=?

 

 

Expert Answers

An illustration of the letter 'A' in a speech bubbles

Solving linear systems using the elimination method is also known as using the addition/subtraction method. The goal is to "eliminate" one of the variables in order to solve the system of equations.

`1/2x+2y=27` 

`x+1/3y =10` 

Simplifying we get:

`x/2 +2y=27` 

`x+y/3=10` 

Now let's look at the first equation. Multiply each term in the equation by 2.

`2 (x/2 +2y) = 2(27)`

`x+4y = 54`

Now let's go back to the second equation. Multiply each term in the equation by 3.

`3(x+ y/3) =3(10)`

`3x+y =30`

Now the two equations will be easier to work with.

`x+4y=54`

`3x+y=30`

Let's eliminate the x variable to solve for y first. To do this multiply the first equation by -3.

`-3(x+4y=54)` >>> `-3x-12y=-162`

`3x+y=30`

Now we have:

`-3x-12y=-162`

`3x +y =30`

The 3x and -3x cancel out. Combine -12y with 1y which is -11y. Finally -162 combined with 30 is -132.

`-11y = -132`

Divide both sides  by -11 to get y alone.

`y=12`

Almost finished. Since you now know what y is, simply plug this value into one of the original equations to solve for x.

`1/2 x +2(12) =27`

`x/2 +24 =27`

`x/2 =3`

`2 (x/2) = 2 (3)`

`x=6`

The solution to the system of equations is

x=6, y=12

See eNotes Ad-Free

Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Get 48 Hours Free Access
Approved by eNotes Editorial