How do you solve the following system: # 3x – y = 28 , 2x+5y=-1 #?

1 Answer
Dec 26, 2015

Answer:

The solution for the system of equations is
#color(blue)(x=139/17, y=(-59)/17#

Explanation:

#3x-y=28#, multiplying this equation by #5#
#15x-color(blue)(5y)=140#......equation #(1)#

#2x+color(blue)(5y)=-1#.......equation #(2)#

Solving by elimination

Adding equations #1# and #2#

#15x-cancelcolor(blue)(5y)=140#

#2x+cancelcolor(blue)(5y)=-1#

#17x=139#

#color(blue)(x=139/17#

Finding #y# by substituting #x# in equation #1#

#3x-y=28#

#3 xx color(blue)(139/17)-y=28#

#(417/17)-y=28#

#(417/17)-28=y#

#(417/17)-476/17=y#

#color(blue)(y=-59/17#