What is the image of the point (-1,7)(−1,7) after a rotation of 90^{\circ}90∘counterclockwise about the origin?

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!

Pls the last one and it has to be like number 6

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