Question

Select the correct answer.

AB and BC form a right angle at point B. If A = (-3,-1) and B = (2, 4), what is the equation of BĆ?
O A x + 3y = 16
OB. 2x+y= 12
OC.-7x - 5y=-48
OD. 7x - 5y = 48

Answer 1

9514 1404 393

Answer:

x + y = 6 (or choice C, see comment)

Explanation:

The equation of the line through point B and perpendicular to AB can be written as ...

(Bx -Ax)(x -Bx) +(By -Ay)(y -By) = 0 . . . . where A = (Ax, Ay) and B = (Bx, By)

(2 -(-3))(x -2) +(4 -(-1))(y -4) = 0

5x +5y -30 = 0

x + y = 6 . . . . . . reduce to standard form

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Additional comment

None of the offered choices describes a line through point B. (See second attachment). We note that several of the lines go through the point (4, 4). The segment joining points (-3, -1) and (4, 4) will be perpendicular to the line -7x -5y = -48, answer choice C.

Please talk to your teacher about this question.