Answer:
Identity is verified.
Step-by-step explanation:
We have to verify the identity 
To prove any identity we always prove one side(either left hand side or right hand side) of the equation equal to the other side.
In this identity we take the left hand side first

(as we know cos(a+b) = cosa×cosb-sina×sinb)


= - sinx ( Right hand side)
Hence identity is proved.
Slope formula is y2-y1/x2-x1.
Using this, we can say that -3 – 2/5 – 0=
1.
Height/width=5/19
5/19=2/x
(5)(x)=(19)(2)
5x=38
5/5x=38/5
x=38/5in or 7.6in
If the long side on both is 9ft and 3ft then 3•3 is 9 so for the short side you do the same. If the short side is 1ft and the other is "j" then it's 1•3 is 3.
1•3=3
Sorry if it's confusing the way I explained it.