Question

Which pair of lines are parallel? Select all that apply

A y=3 - 2x
y = 2x - 3
B. Y=2x – 1
y - 2x = 8
C.y - 4x = 6
y + 4x =-6
D. Y= -3x + 1
y + 4x =x - 1

Answer 1

For this case we have that by definition, the equation of a line in the slope-intersection form is given by:

`y = mx + b`

Where:

m: It's the slope

b: It is the cut-off point with the y axis

By definition, if two lines are parallel then their slopes are equal.

Option A:

`y = -2x + 3\\y = 2x-3`

The slopes are not the same.

Option B:

`y = 2x-1\\y = 2x + 8`

The slopes are the same so the lines are parallel.

Option C:

`y = 4x + 6\\y = -4x-6`

The slopes are not the same.

Option D:

`y = -3x + 1\\y = -4x + x-1 = -3x-1`

The slopes are the same so the lines are parallel.

Answer:

The parallel lines are: Option B and Option D