How do you solve the system #2x + y = 5# and #x - 2y = -5#?

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Answer 1 · 2015-05-22T15:02:57

You can isolate one variable in one equation and then substitute its value in the other, as follows.

Let's, for example, isolate #y# in the first one.

#y=5-2x#

Now, substitute it in the second:

#x-2(5-2x)=-5#
#x-10+4x=-5#
#5x=5#
#x=1#

Substituting this value in the #y=5-2x#,

#y=5-2(1)#
#y=3#