1)
I:y=3x-4
II:9x-3y=14
substitute y into II:
9x-3*(3x-4)=14
9x-9x+12=14
12=14
this is obviously not equal so there is no solution, the lines are parallel
2)
I:y=4x+6
II:5x-y=6
substitute y into II:
5x-(4x+6)=6
5x-4x-6=6
x=12
substiute x into II:
5*12-y=6
-y=6-60
-y=-54
y=54
the solution is (12,54)
