How do you solve this system of equations: #a+ b = 4 and a - b = 10#?

1 Answer
Oct 24, 2017

#a=7# and #b=-3#

Explanation:

If #a+b=4# and we subtract #b# from both sides, we get #a=4-b#

#a-b=10#
Since we know that #a=4-b#, we can substitute #a# with that.
#4-b-b=10->#
#4-2b=10#

Subtract #4# from both sides:
#-2b=10-4->#
#-2b=6#

Divide both sides by #-2#

#(-2b)/(-2)=6/(-2)->#
#b=-3#

Since we know #a=4-b# and #b=-3#, #a=4-(-3)# which is equal to #a=7#.