How many four digit numbers can be formed using the digits ( 3, 4, 5, 6, 7, 8 ) if the first digit is a five and a digit may not be repeated? a. 240 b. 60 c. 48 d. 120 e. 360

Select the number of ways in which a line and a circle can intersect

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

3x + 4y = 5 x- 3y = -7 solve by substitution