Question

linear combination questions :

2x-y=5
2x+y=3

x+y=6
3x - 3y= 18

Answer 1

2x - y = 5
2x + y = 3
-----------add
4x = 8
x = 2
sub 2 in for x in either equation to find y
2x - y = 5
2(2) - y = 5
4 - y = 5
4 - 5 = y
-1 = y
solution (2,-1)
==================
3x - 3y = 18 reduces to x - y = 6
now we have :
x - y = 6
x + y = 6
-----------add
2x = 12
x = 6
now sub 6 in for x in either equation to find y
x + y = 6
6 + y = 6
y = 6 - 6
y = 0
solution is (6,0)
===================
if you have any questions, please ask :)