How do you solve #6x - 2y = -16# and #4x + 4y = -32 #?

2 Answers
Aug 10, 2016

Answer:

#x=-4#
#y=-4#-

Explanation:

#6x-2y=-16# and
#4x+4y=-32#
or
#2x+2y=-16#
or
#x+y=-8#
Adding up the equations #6x-2y=-16# and #2x+2y=-16#
We get
#6x-2y+2x+2y=-16-16#
or
#8x=-32#
or
#x=-32/8#
or
#x=-4#--------------------Ans #1#
By putting the value #x=-4# in the equation #x+y=-8#
We get
#-4+y=-8#
or
#y=4-8#
or
#y=-4#-----------------------Ans #2#

Aug 10, 2016

Answer:

#x = -4 and y = -4#

Explanation:

Neither of the equations is in the simplest form. Let's do that first and see what we end up with.

#6x-2y = -16 " "(div 2)" " rArr 3x-y =-8 ..........A#

#4x + 4y = -32 " " (div 4) " " rArr x+y =-8 ............B#

We notice that #+y and -y# are additive inverses which will add to 0 if we add equations #A and B# together.

#color(white)(................)3x-y =-8 ..........A#
#color(white)(.................)x+y =-8 ............B#

#A+B color(white)(.........) 4x = -16#
#color(white)(.....................)x = -4#
#color(white)(....................)y = -4#