How do you solve the system of equations: x - 2y = -1, 2x - y = 4?

1 Answer
Aug 14, 2015

Answer:

The solutions are:
#color(blue)(x=3,y=2#

Explanation:

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

#color(blue)( 2x) - y = 4#.........equation #(2)#

Now we can solve through elimination as we have the term #color(blue)(2x)# common to both equations:

Subtracting equation #2# from #1#

#cancel(color(blue)(2x)) -4y = -2#
#-cancel(color(blue)( 2x)) + y =- 4#

#-3y=-6#
#color(blue)(y=2#

Now we find #x# by substituting #y# in equation #1#
#x - 2y = -1#
#x = -1+2y#
#x=-1+2*(2)#
#x=-1+4#
#color(blue)(x=3#