IDNStudy.com, ang iyong platform ng sanggunian para sa pangkomunidad na mga sagot. Alamin ang mga detalyadong sagot sa iyong mga tanong mula sa aming malawak na kaalaman sa mga eksperto.

How is 3x-y=8 and x+2y=5 solved by combination (addition)????? 

Sagot :

First, multiply the first equation by 2.

That turns the first equation into:

6x - 2y = 18

That way it can easily be added to the second equation:

6x - 2y = 16
x  + 2y = 5
---------------
7x = 21
==========

As you can see, the y disappeared, which was the objective of this operation.

Now the equations can be solved easily:

7x = 21
x = 3

Insert x=3 in the original equation:

3*3 - y = 8
9 - y = 8
9 = 8 + y
y = 1

So the result is:

x = 3
y = 1