How do you solve #7x+ 6y=-23# and #-9x+ y=47# using substitution?

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Answer 1 · 2016-05-27T22:11:16

#x = -5 and y = 2#

First, change the second equation to be # y = ....#
So, we have the equations:

#7x + 6y = -23 " " and y = 9x + 47#

In the first equation, replace y by #(9x + 47)#

#7x + 6(9x + 47) = -23#

#7x + 54x + 282 = -23#

#61x = -305#

# x = -5#

In the second equation, use #x = -5#

#y =9(-5) + 47 rArr y = 2#

Check for #x = -5 and y = 2#

#7(-5) + 6(2)#
#-35 +12 = -23#