How do you solve the following system?: #3x +11y =-4, -9x +5y = 2#

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Answer 1 · 2016-01-26T10:17:23

#(x,y)=(-7/19,-5/19)#

Solve by elimination:-

#3x+11y=-4,-9x+5y=2#

It is possible to eliminate #-9x# by #3x# if we multiply #3x# by #3# to get #9x#

#rarr3(3x+11y=-4)#

#rarr9x+33y=-12#

Now add both of the equations:-

#rarr(-9x+5y=2)+(9x+33y=-12)=(38y=-10)#

#rarr38y=-10#

#rarry=-10/38=-5/19#

Now substitute the value of y to the first equation:-

#rarr-9x+5(-5/19)=2#

#rarr-9x-25/19=2#

#rarr-9x=2+25/19=63/19#

#rarrx=63/19-:(-9)=63/19*(-1/9)=-63/171=-7/19#

So,#(x,y)=(-7/19,-5/19)#