Problem-solving:

A line segment [tex]AB[/tex] has a midpoint, [tex]M[/tex], at [tex](3,7)[/tex]. [tex]A[/tex] is the point [tex](6,8)[/tex]. What are the coordinates of [tex]B[/tex]?



Answer :

To determine the coordinates of point [tex]\( B \)[/tex] given the midpoint [tex]\( M \)[/tex] of a line segment [tex]\( AB \)[/tex] and one endpoint [tex]\( A \)[/tex], follow these steps:

1. First, recall the midpoint formula for a line segment. If [tex]\( A(x_1, y_1) \)[/tex] and [tex]\( B(x_2, y_2) \)[/tex] are the endpoints of the line segment, the coordinates of the midpoint [tex]\( M \)[/tex] are:
[tex]\[ M \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right) \][/tex]

2. Here, we are given:
- The coordinates of midpoint [tex]\( M \)[/tex] are [tex]\( (3, 7) \)[/tex].
- The coordinates of point [tex]\( A \)[/tex] are [tex]\( (6, 8) \)[/tex].

3. Let the coordinates of point [tex]\( B \)[/tex] be [tex]\( (x_2, y_2) \)[/tex].

4. Using the midpoint formula, set up the equations for the [tex]\( x \)[/tex]-coordinate and [tex]\( y \)[/tex]-coordinate separately:
[tex]\[ 3 = \frac{6 + x_2}{2} \][/tex]
[tex]\[ 7 = \frac{8 + y_2}{2} \][/tex]

5. To find [tex]\( x_2 \)[/tex], solve the first equation:
[tex]\[ 3 = \frac{6 + x_2}{2} \][/tex]
Multiply both sides by 2 to eliminate the fraction:
[tex]\[ 6 = 6 + x_2 \][/tex]
Subtract 6 from both sides:
[tex]\[ 0 = x_2 \][/tex]
So, the [tex]\( x \)[/tex]-coordinate of [tex]\( B \)[/tex] is [tex]\( 0 \)[/tex].

6. Next, solve for [tex]\( y_2 \)[/tex] using the second equation:
[tex]\[ 7 = \frac{8 + y_2}{2} \][/tex]
Multiply both sides by 2 to eliminate the fraction:
[tex]\[ 14 = 8 + y_2 \][/tex]
Subtract 8 from both sides:
[tex]\[ 6 = y_2 \][/tex]
So, the [tex]\( y \)[/tex]-coordinate of [tex]\( B \)[/tex] is [tex]\( 6 \)[/tex].

7. Therefore, the coordinates of point [tex]\( B \)[/tex] are [tex]\( (0, 6) \)[/tex].

In summary, the coordinates of point [tex]\( B \)[/tex] are [tex]\((0, 6)\)[/tex].