Evaluate dx.

-4x + 7y = 1
25 = 2x +5 y

dx = ?

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?

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

Two triangles can be formed with the given information. use the law of sines to solve the triangles. b = 49°, a = 16, b = 14