6x + y = 8 (1) 4x - y = 12 (2)
Method 1 elimination:
-Adding/subtracting the two equations together to eliminate one of the unknowns
(1) + (2)
6x + y = 8
+ 4x - y = 12
10x = 20 (/10)
x= 2
sub 'x=2' into (2)
4(2) - y = 12
8 - y = 12 (+y)
8 = 12 + y (-12)
-4 = y
Method 2 substitution:
-rearranging one of the equations to make an unknown the subject
rearrange (2)
4x - y = 12
4x = y + 12 (+y)
y= 4x - 12 (-12)
sub 'y = 4x - 12' into (1)
6x + '4x - 12' = 8
10x - 12 = 8 (+12)
10x = 20
x = 2
sub 'x=2' into 'y = 4x - 12'
y = 4(2) - 12
y = 8 - 12
y = -4