Please help this question I need all of them

Consider the expression below. 9 + 4(x + 2) – 3.1 select the term that best describes "3" in the given expression. o a. coefficient variable exponent constant

Solve for x and y a x= 13.3 y= 16.7 b x= 23.3 y= 12.5 c x= 7.5 y= 16.7 d x=7.5 y= 12.5

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