How do you solve #3x+7y=10# and #x=18-6y# using substitution?

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Answer 1 · 2016-03-29T23:26:33

#x=-6#
#y=4#

Solution by substitution
#3x+7y=10" "#first equation
#x=18-6y" "#second equation

Use the second equation into the first equation

#3x+7y=10" "#first equation

Now use the second in place of x

#3(18-6y)+7y=10" "#first equation

#54-18y+7y=10#

#-18y+7y=10-54#

#-11y=-44#

#y=(-44)/(-11)#

#y=4#

Use now the second equation #x=18-6y" "#second equation and #y=4# to solve for #x#

#x=18-6y" "#second equation

#x=18-6(4)" "#

#x=18-24#

#x=-6#

God bless....I hope the explanation is useful.