How do you solve for y: #2x + y = 8# , #2x - y = 8#?

1 Answer
May 8, 2018

Answer:

#y=0#

Explanation:

Notice that the #y# terms are additive inverses.
Add the two equations together to eliminate them.

#" "2x+y=8" "...A#
#" "2x-y = 8" "...B#

#A+B" "4x = 16#

#" "x = 4#

If #x =4, " "y=0#

We could have guessed that from looking at the equation.
In one the #y# is added and in the other #y# is subtracted, yet it does not affect the value of the equation at all. The only value of #y# that would allow this to happen would be #y=0#