What I gather from the question is that
has second moment
and variance
, and you're asked to find the expectation and variance of the random variable
.
From the given second moment and variance, we find the expectation of
:

Expectation is linear, so

Using the same variance identity, we have

and

so that

Alternatively, we can use the identity

Answer:
Solving the system of equations:
x: 1
y: 2
Step-by-step explanation:
Plug it in to see if it is right, to make sure of course. Better to be safe than sorry.
Answer:
3/4
Step-by-step explanation:
because it goes 1-2 then 2-3 so then 3-4