What is the answer? Use elimination or substitution to solve #-5x+14y=17" "and" "9x-6y=27#

2 Answers
Dhruv J · EZ as pi · t0hierry
Mar 15, 2018

#x=5 and y=3#

Explanation:

Let the equations be:
#-5x+14y-17=0 " "#(be equation 1)
#" "9x-6y-27=0" "# (be equation 2)

(equation 1 implies)=> #14y=5x+17#

=> #" "y= (5x+17)/14# (be equation 3)

(Substitute into equation 2 )

#9x-6{(5x+17)/14}-27=0" "larr xx 14#

=> #126x-30x-102-378=0#

=> #96x-480=0#

=> #96x=480#

=> #x= 480/96#

=> #x= 5#

Now, substitute into equation 3

=> #y= {5(5)+17}/14" "#(taking x=5)

=> #y= {(25)+17}/14#

=> #y= 42/14#

# y=3#

Barney V.
Mar 15, 2018

#y=3,x=5#

Explanation:

#:.-5x+14y=17---------(1)#

#:.9x-6y=27-----------(2)#

#:.(1)xx9#

#:.-45x+126y=153------(3)#

#:.(2)xx5#

#:.45x-30y=135-------(4)#

#:.(3)+(4)#

#:.96y=288#

#:.y=3#

substitute # y=3# in# (2)#

#:.9x-6(3)=27#

#:.9x-18=27#

#:.9x=27+18#

#:.9x=45#

#:.x=5#

~~~~~~~~~

check:-

Substitute #y=3 #and #x=5# in #(2)#

#:.9(5)-6(3)=27#

#:.45-18=27#

#:.27=27#

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