Julia rides her horse 18 km with a constant speed of 6 km/hr and another 24 km with a constant speed of 12 km/hr. what is her average speed for the total trip? 14 points!

Using the quadratic formula find the zeros of the given polynomial -5x^2+3x-11

Find the volume of the described solid.the solid lies between planes perpendicular to the x-axis at x = 0 and x=7. the cross sectionsperpendicular to the x-axis between these planes are squares whose bases run from the parabolay=-31x to the parabola y = 30/x.a) 441b) 147c) 864d) 882

Ineed to know the answer to this algebra question.