How do you solve the system of equations #20x + 3y = 20# and #- 20x + 5y = 60#?

1 Answer
kamil9234
Mar 16, 2017

#x=-1/2#
#y=10#

Explanation:

#20x+3y=20#
#-20x+5y=60#

You can add all.

#8y=80#
#y=10#

We know that y=10, so we can come back to the one of the first equations. I'll choose #20x+3y=20#.

#20x+3*10=20#
#20x+30=20#
#20x=-10#
#x=-1/2#

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