How do you solve the following system: #-2x + 5y = 20, x + y = 4#?

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Answer 1 · 2018-03-30T09:44:10

Just arrange the equation. Get #x=0# and #y=4#

#-2x + 5y = 20#
#2x +2y = 8#

(after expanding the second equation by 2).

Now combine these equations:

#5y + 2 y = 20+8#

#7y = 28#

#y=28/7#

#y=4#

Now put this value into the second equation:

#x+y=4#

#x=4-y#

#x=4-4=0#