Actually Welcome to the Concept of the Trigonometry.
here, we use the Linear pair property of the adjacent angles.
We know that, all the adjacent angles in a linear pair add to get 180°
so we get as,
=> (n+6) +90°+(2n+3) =180°
=> (n+6) +(2n+3) =180-90
=> 3n+9 = 90
=> 3n= 90-9
=> 3n = 81
hence, n = 81/3
=> n = 27°
thus the value of n is 27° .
Here's the solution ~
Let's find the measure of hypotenuse first, by using Pythagoras theorem ;
Now, let's find the asked values ~
For Cos y :
As we can see that both sin x and Cos y have equal values, therefore The required relationships is equality.
I.e Sin x = Cos y
Hope it helps ~