Question

The set of points R(-1, 1), S(2, 4), T(6, 8) are collinear and the line has a slope of _____.

A.-1
B.1/2
C.1
D.-1/2

Answer 1

Slope= rise/run
= change in y / change in x
= y - y₂/ x-x₂

R(-1, 1), S(2, 4), T(6, 8)

Using points S and T -------(x,y)
S: y=4, x=2
T: y₂=8, x₂=6

Then insert into
Slope=y - y₂/ x-x₂
= 4 - 8/ 2-6
= -4/-4
= 1

The slope is one

Answer 2

OptionC

Explanation:

Let the point R and S form a line.

The slope of line RS would be

Change in y coordinate/change in x coordinate

=
`(4-1)/(2-(-1)) =1`

Now let us consider the line joining S and T

slope of line ST would be

=Change in y coordinate/change in x coordinate

=
`(8-4)/(6-2)) =1`

Thus we find the slopes of RS and ST are equal

Since parallel lines will have equal slopes, here S is the common point

So RS and ST have to be the same line.

Or the three points are collinear with slope = 1