On a number line, the directed line segment from [tex]$Q$[/tex] to [tex]$S$[/tex] has endpoints [tex]$Q$[/tex] at -2 and [tex]$S$[/tex] at 6. Point [tex]$R$[/tex] partitions the directed line segment from [tex]$Q$[/tex] to [tex]$S$[/tex] in a [tex]$3:2$[/tex] ratio. Rachel uses the section formula to find the location of point [tex]$R$[/tex] on the number line. Her work is shown below:

Let [tex]$m=3$[/tex], [tex]$n=2$[/tex], [tex]$x_1=-2$[/tex], and [tex]$x_2=6$[/tex].
1. [tex]$R=\frac{m x_2+n x_1}{m+n}$[/tex]
2. [tex]$R=\frac{3(6)+2(-2)}{3+2}$[/tex]

What is the location of point [tex]$R$[/tex] on the number line?

A. [tex]$\frac{14}{5}$[/tex]
B. [tex]$\frac{16}{5}$[/tex]
C. [tex]$\frac{18}{5}$[/tex]
D. [tex]$\frac{22}{5}$[/tex]



Answer :

To find the location of point [tex]\( R \)[/tex] on the number line, we'll use the section formula, given that point [tex]\( R \)[/tex] divides the directed line segment from point [tex]\( Q \)[/tex] at [tex]\(-2\)[/tex] to point [tex]\( S \)[/tex] at [tex]\(6\)[/tex] in a [tex]\(3:2\)[/tex] ratio.

The section formula for finding the coordinates of a point that divides a line segment in a given ratio is:

[tex]\[ R = \frac{mx_2 + nx_1}{m + n} \][/tex]

Here,
- [tex]\( m = 3 \)[/tex]
- [tex]\( n = 2 \)[/tex]
- [tex]\( x_1 = -2 \)[/tex] (coordinate of [tex]\( Q \)[/tex])
- [tex]\( x_2 = 6 \)[/tex] (coordinate of [tex]\( S \)[/tex])

Substitute these values into the formula:

[tex]\[ R = \frac{3(6) + 2(-2)}{3 + 2} \][/tex]

Now, perform the multiplications and additions inside the fraction:

[tex]\[ R = \frac{18 + (-4)}{5} \][/tex]
[tex]\[ R = \frac{18 - 4}{5} \][/tex]
[tex]\[ R = \frac{14}{5} \][/tex]

Thus, the location of point [tex]\( R \)[/tex] on the number line is:

[tex]\[ \boxed{\frac{14}{5}} \][/tex]