coordinate geometry

[cmr209]

In the xy-coordinate system, if (a,b) and (a + 3, b + k) are two points on the line defined by the equation x = 3y - 7, then k = ?

A) 9

B) 3

C) 7/3

D) 1

E) 1/3


OA - D

[truplayer256]

x=3y-7

Re-write in y=mx+b form.

(x+7)/3=y

x/3+7/3=y

slope=m=1/3

Slope=y2-y1/x2-x1

1/3=b+k-b/a+3-a

1/3=k/3

k=1

D is correct.

[cmr209]

Ah, that's better than the book explained. Thanks!