Use the elimination method to solve. Show all work:
2x + 5y = −3
−15x − 5y = −10

Question

Use the elimination method to solve. Show all work:
 2x + 5y = −3
−15x − 5y = −10

e.mccormick · Answer

Do you know what the elimination method is?

anonymous · Answer

not really :/

e.mccormick · Answer

OK.  That is where you add a multple of one row to another and use the result to replace eiher of the rows.  In this case, you have a 5y and a -5y so the multiple is easy.  1.

e.mccormick · Answer

Does that make sense?  I can set it up so you can see what I am talking about.

anonymous · Answer

Yeah can you set it up I was trying to understand but it's still not very clear to me

e.mccormick · Answer

Yah, without an example, this is a bit hard to grasp.

e.mccormick · Answer

$$\begin{array}{rrr}
2x & +5y &= -3\
-15x & -5y & = -10
\end{array}$$
Now add them together by columns.
$$\begin{array}{rrr}
2x\downarrow & +5y\downarrow &= -3\downarrow\
-15x\downarrow & -5y\downarrow & = -10\downarrow\
2x-15x&+5y-5y&=-3-10\
-13x&0y&=-13\
\end{array}$$

e.mccormick · Answer

Now, you can use that new row to replace one of the existing rows.  In this case, it will not take much after that to solve it.

anonymous · Answer

x=1 y=-1?

e.mccormick · Answer

Lets see.  The x=1 is easy... yah.  That is is.

e.mccormick · Answer

Now can you guess where the name "elimination" comes from?

e.mccormick · Answer

The way they were added together, the y term became 0, and was eliminated.  That is what the name means and is the goal of doing this.  If nothing is negative and matching, you multiply through by a negative that makes something match, -1, -5, -whatever.  Then add and the negative matched term is eliminated.