Question

solve the system using the elimination method.

2x+5y=13
6x+2y=-13

below heres my solution

Answer 1

\[x=-5/2y+13/2, y=4\]

Answer 2

i dont get why i can't get x..

Answer 3

\[
\ \ \ 2x+5y=13\\
\ \ \ 6x+2y=-13\\
\text{First, let's multiply the first equation by -3.}\\
\ \ \ -6x-15y=-39\\
\text{Now let's combine the two equations.}\\
\ \ \ -13y=-52\\
\ \ \ y=4\\
\text{Now we can use }y\text{ to find }x.\\
\ \ \ 2x+5y=13\\
\ \ \ 2x=13-5(4)\\
\ \ \ \ \ \ \ =13-20\\\
\ \ \ \ \ \ =-7\\
\ \ \ x=-\frac72
\]

Answer 4

\[\text{You were on the right track, you just hadn't reduced the expression yet...}\\\text{plug in what you found for }y.\]

Answer 5

do i plug in the original equation or revised one?

Answer 6

Any, because all are equations... just pick one which looks like it requires the least amount of work.

Answer 7

alright. so the solution is (-7/2, 4) ya? :)

Answer 8

do we have to write it as decimal? (-3.5, 4) ?

Answer 9

Indeed -- it's the point where the lines intersect. Since the lines all meet at a common point here, you can derive y from x using any of the equations. I don't know about whether you need to write it as a fraction or decimal but they're equal.