How do you solve the following system?: #-9x -8y =-3, 2x -2y = -4#

1 Answer
Feb 12, 2016

Answer:

The solution for the system of equations is:
#color(green)(x = -13 / (17)#

#color(green)(y =21/17#

Explanation:

#-9x-color(blue)(8y)=-3#.......equation #(1)#

#2x-2y = -4#, multiplying this equation by #4#
#8x-color(blue)(8y) = -16#..........equation #(2)#

Solving by elimination

Subtracting equation #2# from #1#:

#-9x-cancelcolor(blue)(8y)=-3#
#-8x +cancelcolor(blue)(8y) = 16#

#-17x = 13#

#color(green)(x = -13 / (17)#

Finding #y# from equation #1#

#-9x-color(blue)(8y)=-3#

#-9x+ 3 = 8y#

#-9 xx color(green)( -13 / (17))+ 3 = 8y#

#117 / (17)+ 3 = 8y#

#117 / (17)+ 51/17 = 8y#

#168/17 = 8y#

#y =168/(17 xx 8)#

#color(green)(y =21/17#