Me i don’t get this and don’t know the answers

If a || b and b | y, then ? a) x || y. b) x | a. c) a | y. d) a || y.

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

To find the inverse of a number a, one can use the equation f(c) = a-1/c=0 where c is the inverse of a use the secant method of finding roots of equations to find the inverse of a = 2.5 ,er = 0.001%