The angles of a quadrilateral are (x + 10)^o, 2y^o, 90^o and (100 - y)^o, Find y in terms of x

If x^o is obtuse, which of the following is true?

If tan x = 1, evaluate sin x + cos x, leaving your answer in the surd form

If cos (x + 25)^o = sin 45^o, find the value of x