Factor completely 6x^4y^3 + 21x^3y^2 − 9x^2y.

3xy(2x^3y^2 + 7xy − 3x)
3x^2y(2x^2y^2 + 7xy − 3)
3x^2y3& (2x^2 + 7xy − 3)
3x^2y(2x^2y + 7xy − 3y)

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations