3. Point [tex]$B$[/tex] is on line segment [tex]$AC$[/tex]. If [tex]$AB = x + 6$[/tex], [tex]$BC = x + 8$[/tex], and [tex]$AC = 10$[/tex], then find the value of [tex]$x$[/tex].

(6 points)



Answer :

To determine the value of [tex]\( x \)[/tex] given the points on the line segment [tex]\( AC \)[/tex] with [tex]\( AB = x + 6 \)[/tex], [tex]\( BC = x + 8 \)[/tex], and [tex]\( AC = 10 \)[/tex]:

1. Understand the Problem:
- We have a line segment [tex]\( AC \)[/tex] with point [tex]\( B \)[/tex] lying on it.
- The total length of [tex]\( AC \)[/tex] is given as 10 units.
- The lengths [tex]\( AB \)[/tex] and [tex]\( BC \)[/tex] are given as expressions involving [tex]\( x \)[/tex].

2. Formulate the Equation:
Since [tex]\( B \)[/tex] is a point on the line segment [tex]\( AC \)[/tex], the lengths [tex]\( AB \)[/tex] and [tex]\( BC \)[/tex] must sum up to the length [tex]\( AC \)[/tex]. Therefore, we set up the equation:

[tex]\[ AB + BC = AC \][/tex]

3. Substitute the Given Expressions:
Substitute [tex]\( AB = x + 6 \)[/tex], [tex]\( BC = x + 8 \)[/tex], and [tex]\( AC = 10 \)[/tex]:

[tex]\[ (x + 6) + (x + 8) = 10 \][/tex]

4. Simplify the Equation:
Combine like terms on the left side of the equation:

[tex]\[ x + 6 + x + 8 = 10 \][/tex]

[tex]\[ 2x + 14 = 10 \][/tex]

5. Solve for [tex]\( x \)[/tex]:

- Isolate the term with [tex]\( x \)[/tex]:
[tex]\[ 2x + 14 = 10 \][/tex]
Subtract 14 from both sides:
[tex]\[ 2x = 10 - 14 \][/tex]
[tex]\[ 2x = -4 \][/tex]

- Divide both sides by 2:
[tex]\[ x = \frac{-4}{2} \][/tex]
[tex]\[ x = -2 \][/tex]

6. Conclusion:
The value of [tex]\( x \)[/tex] is:

[tex]\[ \boxed{-2} \][/tex]