How do you solve the following system: # 7x − 5y = −11, 7x - y = 10 #?

1 Answer
Jan 3, 2016

Answer:

#color(blue)(x=61/28, y=21/4#

Explanation:

#color(blue)(7x)-5y=-11#....equation #1#

#color(blue)(7x)-y=10#.....equation #2#

Solving by elimination

Subtracting equation #2# from #1#:

#cancelcolor(blue)(7x)-5y=-11#

#-cancelcolor(blue)(7x)+y=-10#

#-4y=-21#

#y=(-21)/(-4)#

#color(blue)(y=21/4#

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

#7x-5y=-11#

#7x=-11+5y#

#7x=-11+5xx(21/4)#

#7x=-11+(105/4)#

#7x=-44/4+(105/4)#

#7x=61/4#

#color(blue)(x=61/28#

The solution for the system of equations is :

#color(blue)(x=61/28, y=21/4#