Question

Which lines are parallel?
y=-3x+1
-3x+y=5
2y=-6x+12

Answer 1

The equation of a straight line is usually written in Slope-Intercept Form :

y = mx + b


Rewrite second and third equations:

-3 x + y = 5

y = 3 x + 5

( Slope = 3 )


2 y = -6 x + 12 Divide both sides with 2

y = -3 x + 6

( Slope = - 3 )



Parallel lines have the same slope.


Lines:

y = - 3 x + 1

and

2 y = -6 x + 12 = -3 x + 6

are parallel.