How do you solve this system of equations: #4x + 6y = - 78 and x - y = - 2#?

Question

1918 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-05-03T02:29:54

#x=-9# and #y=-7#

#x−y=−2# ; #4x+6y=−78#

Step 1: Solve #x−y=−2# for #x#:

#x−y (+y) =−2 (+y)#
(Add #y# to both sides)

#x=y−2#

Step 2: Substitute “#y−2#” for “#x#” in #4x+6y=−78 #:

#4x+6y=−78 #
#4(y−2)+6y=−78#
#10y−8=−78#
(Simplify both sides of the equation)

#10y−8 (+8)=−78 (+8)#
(Add #8# to both sides)

#10y=−70#
#10y/ (10)=−70/ (10)#
(Divide both sides by #10#)

#y=−7#

Step 3: Substitute “#−7#” for “#y#” in #x=y−2# :
(Simplify both sides of the equation)
#x=y−2#
#x= (−7) −2#

#x=−9#

#x=-9# and #y=-7#