On agrid, line j passes through (8, 2) and (–2, –2). line k passes through (–4, 3) and (–6, 8). Are lines j and k parallel, perpendicular, or neither?

Question

please explain how the answer is determined

Answer 1

Hi mia.

 

A few hints, then you may be able to work this out on your own.

 

Two lines are parallel if they have the same slope.

 

Two lines are perpendicular if their slopes are negative inverses of one another. (For example if one slope is 3 and the other is -1/3.)

 

Figure out the slope of each line by forming a fraction from the difference in the y coordinates / difference in the x coordinates:

 

Y #2 - y #1 all over x #2 - x #1.  

 

Do that for each line, and make sure you simplify the fractions. What do you notice about the two fractions?