The base of the isosceles triangle is parallel to x-axis and has both end-points on the parabola y=x(10-x) and its vertex belongs to the x-axis. Find area of the triangle if the length of its base is 8

I'll give brainliest if you answer right : )

Monica build a remote control toy airplane for science project to test the plane she launched it from the top of a building the plane travel a horizontal distance of 50 feet before landing on the ground a quadratic function which models the height of the plane in feet relative to the ground at a horizontal distance of x feet from the building is shown

If f(x) =3x-2 and g(x) =2x+1 fins (f+ g) (x)