8(y+4)-2(y-1)=70-3y help pls

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

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Through non-collinear points there is exactly one plane.