Thread: Points on linear lines HELP!!!

I need help with two questions, and if you could explain how you came to the answer, i would be grateful.

1. Which of the following points do not lie on the line:

2y + 5x - 4 = 0

a. ( -0.8 , 0 )
b. ( -1 , 0.5 )
c. ( 0 , 2 )
d. ( 2 , 3)

2. P is the point ( 3 , 5 ). Q is the point ( -1 , 9 ). R is the midpoint of PQ.

Which of the following does R lie on?

a. y = x + 6
b. y = x + 8
c. y = x - 6
d. y = x - 8

Thanks in advanced to anyone who can help.

Originally Posted by nugiboy

I need help with two questions, and if you could explain how you came to the answer, i would be grateful.

1. Which of the following points do not lie on the line:

2y + 5x - 4 = 0

a. ( -0.8 , 0 )
b. ( -1 , 0.5 )
c. ( 0 , 2 )
d. ( 2 , 3)

first solve for y:



now, plug in the x-coordinates of the points given and see if you get back the y-coordinates given, if you don't, then that point is not on the line.

example, try (c): plug in x = 0, we get:



since 2 was the y-coordinate given, this point is on the line. thus, this is not the point we are looking for

2. P is the point ( 3 , 5 ). Q is the point ( -1 , 9 ). R is the midpoint of PQ.

Which of the following does R lie on?

a. y = x + 6
b. y = x + 8
c. y = x - 6
d. y = x - 8

Thanks in advanced to anyone who can help.

use the midpoint formula to find R.

recall: the midpoint between two points and is given by:



once you have found R, do a similar procedure as in the previous problem