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4 votes
Solve the system of equations 2x+y=-2 and -9x-3y=18 by combining the equations.

User Imbr
by
5.5k points

1 Answer

7 votes

Answer:

2x+y=-2

-9x-3y=18

So what you would do is see which one you would like to get rid of (either x, or y in this situation get rid of y)

multiply y by postive 3

3(2x+y=-2)

6x+3y=-6

-9x-3y=18 (both y's cross out since 3y+-3y is equal to zero)

-----------------

-3x=-24 (divide both sides by -3)

--- ---

-3 -3

x= 8 (neg/neg=positive)

Then figure out the x so use either the first or second equation

so in this case I will use the first equation (plug in the x for 8)

2(8)+y=-2

16+y=-2

-16 -16

---------------

y=-18

Check:

2x+y=-2

2(8)+y(-18)=-2

16+-18=-2

-2=-2 (therfore you know that you are right)

Ansers:

y=-18

x=8

Hope this helps!

User Peace Ngara
by
6.3k points
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