How do you solve the system of equations #3x + y = 10# and #x - y = 2#?

Question

5988 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-12-05T20:06:02

#x = 3 and y = 1#

This is the best scenario you can get with a system of equations. The y-terms are additive inverses which means they add to zero.

#" "3x +y = 10# ................................A
#" "x -y = 2# .................................B

#A + B" "4x = 12" "# there is only x, you can solve for x.
#" "x = 3#

Substitute 3 for x in one of the equations - let's use B

#x-y = 2#
#3 -y = 2#
#3-2 = y#

#1 = y#

Check: #3x+y = 10#
#3(3) + (1)#
#=10#