How do you find the solution of the system of equations #3x - y = 9 # and #2x + y = 6 #?

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Answer 1 · 2015-05-06T04:51:19

We can add the two equations to eliminate #y#

Adding the 2 equations will give us:

#(3x - y) +(2x + y) = 9 + 6 #

#3x - cancel(y) +2x + cancel(y) = 15#

#5x= 15#
#color(blue)(x = 3)#

Substituting this value of #x# in the first equation we get #y# :

we are given:
# 3x - y = 9#

# 3*3- y = 9#
# 9 - y= 9 #
# 0 = y#

#color(blue)(y=0)#

The solution to these system of equations is:

#color(green)(x = 3 , y = 0#