A straight line in the xy- plane has y-intercept of 49 . On this line the x-coordinate of the point is 71 and y-coordinate is 12 then what is the slope of the line?
Choose the correct choice from the following:
A) 0.5 B) 0.51 C) - 0.52 D) 0.31 E) - 0.49

Rationale: "eq of line = y = mx + c c = 49 x = 71 y = 12 substitute given : m = ( y - c ) / x = ( 12 - 49 ) / 71 = - 37 / 71 = - 0.52 correct option is c"
Answer: C