Question

Select the correct answer.
AB and BC form a right angle at point B. If A= (-3,-1) and B = (4,4), what is the equation of
O A.
x + 3y = 16
B. 2x + y = 12
C.-7x- 5y = -48
D. 7x - 5y = 48​

Answer 1

Answer:

  C.  -7x- 5y = -48

Step-by-step explanation:

The vector AB is ...

  AB = B -A = (4, 4) -(-3, -1) = (4+3, 4+1) = (7, 5)

The dot-product of this vector and the one in the direction of the line through B will be 0:

  (7, 5)·(x -4, y -4) = 0

  7(x -4) +5(y -4) = 0

  7x +5y -48 = 0

Multiplying by -1 gives the form we see in answer choice C:

  -7x -5y = -48