How do you solve the system of equations #3x + 8y = 18# and #- 8x - 10y = 20#?

1 Answer
Lucy
Apr 3, 2018

#x=-10#
#y=6#

Explanation:

#3x+8y=18# --- (1)
#-8x-10y=20# --- (2)

From (1)
#3x=18-8y#
#x=6-8/3y# --- (3)

Sub (3) into (2)
#-8(6-8/3y)-10y=20#
#-48+64/3y-10y=20#
#34/3y=68#
#y=6# --- (4)

Sub (4) into (3)
#x=6-8/3(6)#
#x=-10#

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