Select the correct answer.

[tex]$\overleftrightarrow{A B}$[/tex] and [tex]$\overleftrightarrow{B C}$[/tex] form a right angle at point [tex]$B$[/tex]. If [tex]$A = (-3, -1)$[/tex] and [tex]$B = (4, 4)$[/tex], what is the equation of [tex]$\overleftrightarrow{B C}$[/tex]?

A. [tex]$x + 3y = 16$[/tex]
B. [tex]$2x + y = 12$[/tex]
C. [tex]$-7x - 5y = -48$[/tex]
D. [tex]$7x - 5y = 48$[/tex]



Answer :

To determine the equation of the line [tex]\( \overleftrightarrow{BC} \)[/tex], given that [tex]\( \overleftrightarrow{AB} \)[/tex] and [tex]\( \overleftrightarrow{BC} \)[/tex] form a right angle at point [tex]\( B \)[/tex], and the coordinates of points [tex]\( A \)[/tex] and [tex]\( B \)[/tex] are [tex]\( A = (-3, -1) \)[/tex] and [tex]\( B = (4, 4) \)[/tex], follow these steps:

1. Calculate the slope of [tex]\( \overleftrightarrow{AB} \)[/tex]:

The slope [tex]\( m \)[/tex] of a line through two points [tex]\((x_1, y_1)\)[/tex] and [tex]\((x_2, y_2)\)[/tex] is given by:
[tex]\[ m = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]

Substituting [tex]\(A\)[/tex] and [tex]\(B\)[/tex] coordinates:
[tex]\[ m_{AB} = \frac{4 - (-1)}{4 - (-3)} = \frac{4 + 1}{4 + 3} = \frac{5}{7} \][/tex]

2. Determine the slope of [tex]\( \overleftrightarrow{BC} \)[/tex]:

Because [tex]\( \overleftrightarrow{AB} \)[/tex] and [tex]\( \overleftrightarrow{BC} \)[/tex] are perpendicular, the slope [tex]\( m \)[/tex] of [tex]\( \overleftrightarrow{BC} \)[/tex] is the negative reciprocal of the slope of [tex]\( \overleftrightarrow{AB} \)[/tex]:
[tex]\[ m_{BC} = -\frac{1}{m_{AB}} = -\frac{1}{\frac{5}{7}} = -\frac{7}{5} \][/tex]

3. Find the equation of the line [tex]\( \overleftrightarrow{BC} \)[/tex]:

The equation of a line in point-slope form is:
[tex]\[ y - y_1 = m(x - x_1) \][/tex]
Using point [tex]\( B = (4, 4) \)[/tex] and [tex]\( m_{BC} = -\frac{7}{5} \)[/tex]:
[tex]\[ y - 4 = -\frac{7}{5}(x - 4) \][/tex]

4. Convert to slope-intercept form:

Solving for [tex]\( y \)[/tex]:
[tex]\[ y - 4 = -\frac{7}{5} x + \frac{28}{5} \][/tex]
[tex]\[ y = -\frac{7}{5}x + \frac{28}{5} + 4 \][/tex]
[tex]\[ y = -\frac{7}{5}x + \frac{28}{5} + \frac{20}{5} \][/tex]
[tex]\[ y = -\frac{7}{5}x + \frac{48}{5} \][/tex]

5. Convert to general form [tex]\( ax + by = c \)[/tex]:

Multiply through by 5 to clear the fraction:
[tex]\[ 5y = -7x + 48 \][/tex]
Rearrange to general form:
[tex]\[ 7x + 5y = 48 \][/tex]

Compare to the given options:

- Option A: [tex]\( x + 3y = 16 \)[/tex]
- Option B: [tex]\( 2x + y = 12 \)[/tex]
- Option C: [tex]\( -7x - 5y = -48 \)[/tex]
- Option D: [tex]\( 7x - 5y = 48 \)[/tex]

None of the options match [tex]\( 7x + 5y = 48 \)[/tex].

Therefore, the equation of [tex]\( \overleftrightarrow{BC} \)[/tex], given the points and right angle at [tex]\( B \)[/tex], is confirmed by running through the correct procedures and calculations as:
[tex]\[ \boxed{\text{None}} \][/tex]