How do you solve the system of equations #14x + 18y = - 18# and #- 5x - 9y = 27#?

2 Answers
Dec 5, 2016

x=9
y=-8

Explanation:

Elimination method would be best to use here. Multiply the second equation by 2, it becomes -10x-18y=54. Now add this to the first equation 14x +18y =-18. Y term would thus get eliminated and the result would be

4x= 54-18= 36, giving x=9

Now substitute x=9 in -5x -9y=27. This would give

-45-9y=27 Or, -9y= 45+27= 72
Thus y= 72/(-9)= -8

Dec 5, 2016

#x=9#
#y=-8#

Explanation:

#14x+18y=-18#
#-5x-9y=27#

Multiply the second equation by #2#

#14x+18y=-18#
#-10x-18y=54#

and sum member by member:

#14x cancel(+18y) -10x cancel(-18y) =-18+54#

#4x=36#

#x=9#

Now substitute the value of #x# in either equation, e.g. the second one:

#-90-18y=54#

#-18y=144#

#y=-8#