How do you solve by elimination #8x + 3y= -9# and #-8x + y = 29#?

1 Answer
May 13, 2015
  • We can Add the two equations to eliminate #x#

#8x + 3y= -9#
#-8x + y = 29#
.________

#(cancel(8x)+(-cancel(8x))) +(3y+y) = -9+29#

# 4y = 20#

Dividing both sides by 4, we get :

#(4y)/4 = 20/4#

# y = 5#

Substituting # y = 5# in the second equation, we get:

#-8x + 5 = 29#

Transposing 5 to the other side we get:

# - 8x = 29 - 5#

# -8x = 24#

Dividing both sides by #-8# will give us:

#(-8x)/-8 = 24/-8#

# x = -3#

The Solution to the above equations is:

#color(green)(x = -3 and y = 5#

  • Verify your answer

Substitute these values of #x and y# in any of the equations and check if both sides equal each other.