# Thread: Points on linear lines HELP!!!

1. ## 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.

2. 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:

$\displaystyle y = - \frac 52x + 2$

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:

$\displaystyle y = - \frac 52(0) + 2 = 2$

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 $\displaystyle (x_1,y_1)$ and $\displaystyle (x_2,y_2)$ is given by:

$\displaystyle \mbox {Midpoint } = \left( \frac {x_1 + x_2}2, \frac {y_1 + y_2}2 \right)$

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