What is the value of x when f(x)=-4

Find the slope and the y-intercept if there's one and the equation of the line given these two points( 3, 2) and( 3, -4)

Sara can take no more than 22 pounds of luggage on a trip. her suitcase weighs 112 ounces. how many more pounds can she pack without going over the limit?

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