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How do you solve by substitution #4x-7y=10# and #y= x-7#?

1 Answer

Jun 4, 2015

Given
[1]#color(white)("XXXX")##4x-7y = 10#
[2]#color(white)("XXXX")##y = x-7#

Using [2] substitute #(x-7)# for #y# in [1]
[3]#color(white)("XXXX")##4x - 7(x-7) = 10#

Simplifying
[4]#color(white)("XXXX")##-3x +49 = 10#
[5]#color(white)("XXXX")##x = 13#

Using [5] substitute #(13)# for #y# in [2]
[6]#color(white)("XXXX")##y = (13) -7#
[7]#color(white)("XXXX")##y= 6#

#(x,y)=(13,6)#

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