Answer:
2 one that's the right one
Make the whole number as an improper fraction. example, 2 7/12 would be 31/12 and then you can multiply 8/1 x 31/12
Answer: -2*(9n-4)/9
Step-by-step explanation: The -2*(9n-4) is over the 9
Let the numbers be x and y. Then xy = -30 and x+y = -3.
Solve xy = -30 for y: y = -30/x
subst. -30/x for y in x+y= -3: x - 30/x = -3
Multiply all 3 terms by x: x^2 - 30 = -3x, so x^2 + 3x - 10 = 0
Solve this quadratic equation for x. x: {-5, 2}
If x = -5, then x+y = -3 becomes -5 + y = -3, and y = 2.
You should check to determine whether x=2 is also correct. If it is, what is the corresponding y value?
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.
