Using the completing-the-square method, rewrite f(x) =x^2+4x-1 in vertex form. this would help a lot thanks!

The average number of vehicles waiting in line to enter a parking lot can be modeled by the function f left parenthesis x right x squared over 2 left parenthesis 1 minus x right parenthesis endfraction , where x is a number between 0 and 1 known as the traffic intensity. find the rate of change of the number of vehicles waiting with respect to the traffic intensity for the intensities (a) xequals0.3 and (b) xequals0.6.

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

Oliver had $50 on the day before his birthday. after he recived some money for his birthday , he had $75. write and solve eqaution to find how much money oliver received for his birthday. x+50=75