Which equations are parallel lines?

Question

y = 5x/3 + 4
y = -3x/5 - 7
y = 2x + 8
y = 2x - 4

Answer 1

Parallel lines have the same slope.
y = mx+c
m is the gradient (slope)
so the third and the fourth equations have the same gradient which is 2, so these represent lines that are parallel.

The first and the second equations have lines that are perpendicular, since the product of their gradients is -1:
(5/3) * (-3/5) = -(5*3) / (3*5) = -1

Answer 2

All equations are in slope-intercept form, y = mx + b
where m is the slope.

So the slopes for the equations are:

(5/3)
(-3/5)
(2)
(2)

Two parallel lines have the same slope, therefore

y = 2x + 8
y = 2x - 4

are parallel.

Answer 3

Parallel lines have the same slope.

The following lines have slope = 2:

y = 2x + 8
y = 2x - 4

Answer 4

y=2x+8 and y=2x-4 are parallel lines because they have the same slope.equations having the same slope are parallel lines.these slopes are obtained easily since all the given equations are in the slope-intercept form.in a slope-intercept form of an equation,the number beside x is the slope of a given equation.

Answer 5

y=2x+8 and y=2x-4 represents parallel lines because their slopes are equal.
compare these equation with y=mx+c, where m is slope of line.in these two equations slope is 2.

Answer 6

Flori has the correct answer. The rule:
For linear equations in the form y=mx+b, all that is required for parallelism is that their gradients are equal. e.g. given any two linear equations:

y1 = mx+b and y2 = nx + b

Line y1 is parallel to line y2 iff (if and only if) m=n.

Enrichment: Line y1 is perpendicular to y2 iff
mn = -1 and neither line is a coordinate axis.

Answer 7

y = 2x + 8
y = 2x - 4

since they both have the same slope, they are parallel

The first 2 are perpendicular.

Answer 8

Parallel lines have the same slope. Linear equations have the form:

y = mx + b

where m is the slope.

Now you tell me.

Answer 9

y=2x+8
y=2x-4