How do you solve the system using elimination #3a + b = -1# and #-3a + b = 5#?

Question

2949 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-06-03T18:31:20

Given:

#3a+b = -1#

#-3a+b=5#

First add both equations together to get:

#4 = -1 + 5 = (3a+b) + (-3a+b) = 2b#

Divide both ends by #2# to get #b=2#

Then subtract both equations to get:

#-6 = -1-5 = (3a+b)-(-3a+b) = 6a#

Divide both ends by #6# to get #a=-1#