How do solve the following linear system?: #2x + 4 = -4y, 7x + 6y + 11 = 0 #?

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Answer 1 · 2017-06-17T17:16:22

#(-5/4,-3/8)#

First, solve one of the equations for #x#. It doesn't matter which one.

#2x+4 = -4y#

#2x=-4-4y#

#x=-2-2y#

Next, plug this equation for #x# into the other equation

#7color(red)(x)+6y+11=0#

#7(color(red)(-2-2y))+6y+11=0#

#-14-14y+6y+11=0#

#-14-8y+11=0#

#-3-8y=0#

#-8y=3#

#y=-3/8#

Finally, plug this solution for #y# into the equation for #x#

#x=-2-2y#

#x=-2-2(-3/8)#

#x=-2+6/8#

#x=-16/8+6/8=-10/8=-5/4#