How do you decide whether the graphs of the two equations are parallel lines: #y=2x-1, y=-2x+1#?

2 Answers
Dec 5, 2016

Answer:

Not parallel

Explanation:

Lines are parallel, if their slope is same.

Slope of y= 2x-1 is 2
Slope of y= -2x+1 is -2.

The slopes are not same (not equal), hence lines are not parallel

Dec 5, 2016

Answer:

Both lines are expressed in slope intercept form #y=mx+p# where #m# is the slope.

To be parallel they would have to have the same slope. This is not the case so they are not parallel.

Explanation:

More in detail if the two lines

#y=2x-1#
#eta=-2x+1#

were parallel, then #y-eta# would be constant.

But:

#y-eta = 2x-1-(-2x+1) =4x-2#

and it is also obvious that the two lines cross for #x=1/2#