How do you solve #3x -y = 4# and #x + 2y = 13#?

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Answer 1 · 2015-12-21T16:12:42

The solution for the system of equations is
#color(blue)(x=3, y=5#

#3x-y=4#, multiplying by #2#
#6x-color(blue)(2y)=8#.....equation #1#

#x +color(blue)(2y)=13#....equation #2#

Solving by elimination

Adding equations #1# and #2#

#6x-cancelcolor(blue)(2y)=8#

#x +cancelcolor(blue)(2y)=13#

#7x=21#

#x=21/7#

#color(blue)(x=3#

Finding #y# from equation #1#

#3x-y=4#

#3x-4=y#

#3 xx color(blue)(3)-4=y#

#9 -4=y#

#color(blue)(y=5#