I think maybe the second one I’m not fully sure but I hope this might help
Answer:
-8a + 12
Step-by-step explanation:
-2(4a - 6)
-2(4a) - -2(6)
-8a - -12
-8a + 12
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.
Answer:
125 m
Step-by-step explanation:
The path of Kristina is in the shape of a right triangle where, the perpendicular is the path from the McDonalds to the three-way junction which is 145 m and the shortest distance between the McDonalds and the church is 191.442 m.
By Pythagoras theorem

Christina had to travel 125 m from the three-way junction to the church.