How do you solve the following system?: # 3x+3y= -7 , 3x − y = 30 #

1 Answer
Feb 1, 2017

Answer:

#y=-9 1/4, x=6 11/12#

Explanation:

#3x+3y=-7 -------1#

#3x-y=30--------2#

#4y=-37#----------------------------------#1-2#

#y=-37/4#

#y=-9 1/4#

substitute # y= -37/4# in-------2

#3x-(-37/4)=30#

#3x+37/4=30#

#3x=30-37/4#

#3x=120/4-37/4#

#3x=83/4#

multiply both sides by 4

#12x=83#

#x=83/12#

#x=6 11/12#

substitute #y=-37/4, x= 83/12# in-------2

#3(83/12)-(-37/4)=30#

#249/12+37/4=30/1#

#(249+111=360)/12#

#249/12+111/12=360/12#

#360/12=360/12#