On a number line, the directed line segment from [tex]\(Q\)[/tex] to [tex]\(S\)[/tex] has endpoints [tex]\(Q\)[/tex] at [tex]\(-14\)[/tex] and [tex]\(S\)[/tex] at [tex]\(2\)[/tex]. Point [tex]\(R\)[/tex] partitions the directed line segment from [tex]\(Q\)[/tex] to [tex]\(S\)[/tex] in a [tex]\(3:5\)[/tex] ratio.

Which expression correctly uses the formula [tex]\(\left(\frac{m}{m+n}\right)\left(x_2-x_1\right)+x_1\)[/tex] to find the location of point [tex]\(R\)[/tex]?

A. [tex]\(\left(\frac{3}{3+5}\right)(2-(-14))+(-14)\)[/tex]

B. [tex]\(\left(\frac{3}{3+5}\right)(-14-2)+2\)[/tex]

C. [tex]\(\left(\frac{3}{3+5}\right)(2-14)+14\)[/tex]

D. [tex]\(\left(\frac{3}{3+5}\right)(-14-2)-2\)[/tex]



Answer :

To determine the correct location of point [tex]\( R \)[/tex] that partitions the directed line segment from [tex]\( Q \)[/tex] to [tex]\( S \)[/tex] in the ratio 3:5, we will use the formula for finding the coordinates of a point dividing a segment in a given ratio:

[tex]\[ x_R = \left( \frac{m}{m + n} \right)(x_2 - x_1) + x_1 \][/tex]

Here, the points and ratios are:
- [tex]\( Q \)[/tex] has coordinates [tex]\( x_1 = -14 \)[/tex]
- [tex]\( S \)[/tex] has coordinates [tex]\( x_2 = 2 \)[/tex]
- The ratio in which [tex]\( R \)[/tex] divides [tex]\( QS \)[/tex] is [tex]\( 3:5 \)[/tex], where [tex]\( m = 3 \)[/tex] and [tex]\( n = 5 \)[/tex]

By substituting these values into the formula:

[tex]\[ x_R = \left( \frac{3}{3+5} \right)(2 - (-14)) + (-14) \][/tex]

Let's break this down step by step:

1. Calculate the sum of the ratio components:
[tex]\[ 3 + 5 = 8 \][/tex]

2. Substitute the ratio into the fraction:
[tex]\[ \frac{3}{8} \][/tex]

3. Compute the difference between [tex]\( x_2 \)[/tex] (the coordinate of [tex]\( S \)[/tex]) and [tex]\( x_1 \)[/tex] (the coordinate of [tex]\( Q \)[/tex]):
[tex]\[ 2 - (-14) = 2 + 14 = 16 \][/tex]

4. Multiply the fraction by the difference calculated in step 3:
[tex]\[ \frac{3}{8} \times 16 = 6 \][/tex]

5. Finally, add this result to [tex]\( x_1 \)[/tex] (the coordinate of [tex]\( Q \)[/tex]):
[tex]\[ 6 + (-14) = -8 \][/tex]

So, the location of point [tex]\( R \)[/tex] is [tex]\(-8\)[/tex].

Thus, the correct expression that correctly uses the formula is:

[tex]\[ \left( \frac{3}{3+5} \right)(2-(-14)) + (-14) \][/tex]

Which matches the option:

[tex]\[ \left( \frac{3}{3+5} \right)(2 - (-14)) + (-14) \][/tex]