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Use the elimination method to solve the system of equations. Choose the correct ordered pair. 4x4y-27 5x-y-18

A. (6,9)
B. (2,8)
C. (3,6)
D. (5,7)

1 Answer

3 votes

Answer:

(5,7)

Explanation:

4x+y=27

5x-y=18

Since we want to solve this by elimination we need the lines to be in the same form, and a column with opposite variables or same variables. We actually have both of these.

Both equations are in the form ax+by=c.

The column that contains the y's, we have opposites there. That is the opposite of y is -y. When you add opposites, you get 0.

So we just add vertically now.

4x+y=27

5x-y=18

--------------Add

9x+0=45

9x =45

Divide both sides by 9:

x =45/9

Simplify:

x =5

Now to find y, you just need to use one of your equations (just pick one) along with x=5.

I guess I will choose 4x+y=27 with x=5.

4x+y=26 with x=5

4(5)+y=27

20+y=27

Subtract 20 on both sides:

y=27-20

y=7

So the solution (x,y) is (5,7).

User JVMX
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