Solve using the elimination method.

Question

Solve using the elimination method.
x+y=12
-x+5y=12

Select the correct choice below and fill in any answer boxes present in your choice.

A) The solution of the system is ___. (type order pair)
b) There are infinitely many solutions.
c) There is solution.

Answer 1

Hi Kenny,

 

x+y=12.............eqn 1

-x+5y=12..........eqn 2

 

adding eqn 1 & 2,

 

6y =24

 

y= 4

substituting value of y = 4 in eqn 1, we get

 

x+4=12

x=8

 

ans : A (8,4) 

Answer 2

x + y = 12
-x + 5y = 12

 

To solve by the elimination method, you just add or subtract the two equations (or multiples or one or both of them) in a way that eliminates one of the variables.

 

In this case, you can add the two equations as is, and the x's will cancel out:

 

x + y = 12
-x + 5y = 12

 

x + -x + y + 5y = 12 + 12

6y = 24

y = 4

 

Then use y=4 in one of the equations to solve for x.  The easier equation to use is x+y=12, because that quickly shows you that x = 8.

 

So the answer is A and the pair is (8, 4)