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On a number line, the directed line segment from [tex]\(Q\)[/tex] to [tex]\(S\)[/tex] has endpoints [tex]\(Q\)[/tex] at [tex]\(-2\)[/tex] and [tex]\(S\)[/tex] at [tex]\(6\)[/tex]. Point [tex]\(R\)[/tex] partitions the directed line segment from [tex]\(Q\)[/tex] to [tex]\(S\)[/tex] in a 3:2 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]\(R=\frac{mx_2 + nx_1}{m+n}\)[/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]


Sagot :

To find the location of point [tex]\(R\)[/tex] on the number line, we need to correctly apply the section formula given the ratio and endpoints. Here's the step-by-step solution:

1. Identify the given points and the ratio:
- The endpoint [tex]\(Q\)[/tex] is at [tex]\(-2\)[/tex],
- The endpoint [tex]\(S\)[/tex] is at [tex]\(6\)[/tex],
- The ratio in which [tex]\(R\)[/tex] partitions the segment from [tex]\(Q\)[/tex] to [tex]\(S\)[/tex] is [tex]\(3:2\)[/tex].

2. Let [tex]\(m = 3\)[/tex] and [tex]\(n = 2\)[/tex] represent the parts of the ratio. Let [tex]\(x_1 = -2\)[/tex] (coordinate of [tex]\(Q\)[/tex]) and [tex]\(x_2 = 6\)[/tex] (coordinate of [tex]\(S\)[/tex]).

3. Use the section formula:
[tex]\[ R = \frac{m x_2 + n x_1}{m + n} \][/tex]

4. Substitute the given values into the formula:
[tex]\[ R = \frac{3(6) + 2(-2)}{3 + 2} \][/tex]

5. Perform the multiplications inside the numerator:
[tex]\[ R = \frac{18 + (-4)}{5} \][/tex]

6. Simplify the numerator:
[tex]\[ R = \frac{14}{5} \][/tex]

Thus, the location of point [tex]\(R\)[/tex] on the number line is [tex]\(\frac{14}{5}\)[/tex].

Hence, the correct answer is [tex]\(\frac{14}{5}\)[/tex].