How do you solve the following system?: #y=2x + 3 , x + 3y = -3 #

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Answer 1 · 2015-12-24T20:47:19

#(-12/7, -3/7)#

You can solve this system of equation by substitution

#color(red)(y = 2x +3#
#x + 3y = -3#

Substitute #y =2x + 3# into the second equation

#x+ 3(color(red)(2x+3)) = -3 #

Distribute and combine like terms

#x + 6x + 9 = -3#

#7x + 9 = -3#
#7x = -3 -9#

#7x = -12#

#x = -12/7#

Then re-substitute #x = -12/7# into #y= 2x+3# to solve for #y#

#y = 2( -12/7) + 3#
#=> y = -24/7 + 21/7#
#=> y = -3/7#