How do you solve #2x+9y=10# and #x=4-4y#?

1 Answer
May 21, 2016

Answer:

The solution for the system of equations is:
#color(green)(x = -4#

#color(green)(y=2#

Explanation:

#2x + 9y =10#.......equation #(1)#

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

Solving by substitution:

Substituting equation #2# into equation #1:#

#2x + 9y =10#

#2 * (color(blue)( 4 - 4y)) + 9y =10#

#color(blue)(8 - 8 y) + 9y =10#

#8 + y =10#

# y =10 - 8#

#color(green)(y=2#

Finding #x# from equation #2:#

#x = 4-4y#

#x = 4-(4*2)#

#x = 4-8#

#color(green)(x = -4#