Question

Select the correct answer.

 and  form a right angle at point B. If A = (-3, -1) and B = (4, 4), what is the equation of ?

A.

x + 3y = 16

B.

2x + y = 12

C.

-7x − 5y = -48

D.

7x − 5y = 48

 

Answer 1

Slope of AB = (difference of y coords)/(difference of x coords)=(4-(-1))/(4-(-3))=5/7.

The slope of the perpendicular is the negative inverse of this slope=-7/5.

Equation in slope intercept form is y-4=(-7/5)(x-4).

Multiply through by 5: 5y-20=-7(x-4)=-7x+28, so -7x-5y=-48 is the equation of the perpendicular through B, answer C.