Answer:
314
Step-by-step explanation:
23 3/4. because if it was 0.25, then you know that it is a quarter, 0.50 is half, therefore 0.75 is three quarters
Answer:
8by + 2ax - 4bx - 4ay
Step-by-step explanation:
I assume you mean expand so:
(a - 2b)(3x - 5y) + (2b - a)(x - y)
3ax - 5ay - 6bx + 10by + 2bx - 2by - ax + ay
Now collect like terms:
2ax - 4ay - 4bx + 8by
This is your answer but in a better order:
8by + 2ax - 4bx - 4ay
A is false but R is true (the mean of the last 3 values is not 8 since x=7)
Looks like a badly encoded/decoded symbol. It's supposed to be a minus sign, so you're asked to find the expectation of 2<em>X </em>² - <em>Y</em>.
If you don't know how <em>X</em> or <em>Y</em> are distributed, but you know E[<em>X</em> ²] and E[<em>Y</em>], then it's as simple as distributing the expectation over the sum:
E[2<em>X </em>² - <em>Y</em>] = 2 E[<em>X </em>²] - E[<em>Y</em>]
Or, if you're given the expectation and variance of <em>X</em>, you have
Var[<em>X</em>] = E[<em>X</em> ²] - E[<em>X</em>]²
→ E[2<em>X </em>² - <em>Y</em>] = 2 (Var[<em>X</em>] + E[<em>X</em>]²) - E[<em>Y</em>]
Otherwise, you may be given the density function, or joint density, in which case you can determine the expectations by computing an integral or sum.
