How do you solve this system of equations using substitution?

Question

#y=-3#
#-5x-3y=14#

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Answer 1 · 2017-03-15T19:23:39

# x = -1" "and" " y --3#

#y = -3" and " -5x-3y = 14#

This is a really simple system of equations to solve, because we have already been given the value of one of the variables:

#color(red)(y =-3)#

So now you can substitute #-3# for #y# in the other equation:

#-5x -3color(red)(y) = 14#

#-5x -3(color(red)(-3)) = 14#

#-5x +9 = 14#

#-5x = 14-9#

#-5x =5" "larr div -5#

#x = 5/-5 = -1#