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How do you solve the following linear system #-4x +9y = 5 , x - 4y = -3 #?

1 Answer

Jun 15, 2016

#x=1; y=1#

Explanation:

First, let's obtain x in the second equation:
#x=4y-3#

then let's substitute its value in the first one:
#-4(4y-3)+9y=5#

then, by simplifying:
#-16y+12+9y=5#
#-16y+9y=-12+5#
#-7y=-7#
#y=1#

and now let's substitute the value of y in
#x=4y-3#

so that
#x=4*1-3#
#x=1#

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