How do you solve #-13x-17y=15# and #x+y=-3#?

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Answer 1 · 2017-02-19T17:23:48

#x=-9# and #y=6#

#-13x-17y=15#
#x+y=-3#

From the second equation, determine a value for #x#.

#x+y=-3#

Subtract #y# from each side.

#x=-3-y#

In the first equation, substitute #x# with #color(red)((-3-y))#.

#-13x-17y=15#

#-13color(red)((-3-y))-17y=15#

Open the brackets and simplify. The product of two negatives is a positive.

#39+13y-17y=15#

#39-4y=15#

Subtract #39# from both sides.

#-4y=-24#

Divide both sides by #-4#.

#y=6#

in the second equation, substitute #y# with #color(blue)6#.

#x+y=-3#

#x+color(blue)6=-3#

Subtract #6# from both sides.

#x=-9#