You will need to work left to right.
p - 10p + -5p +14p - -9p - 2 = -20
-9p + -5p +14p - -9p - 2 = -20
-14p +14p - -9p - 2 = -20
0p- -9p - 2 = -20
9p - 2 = -20
Then you will want to eliminate 2 by adding it to both sides
9p = -18
Then divide by 9 to isolate P
p=-2
The answer is B because it includes all of the numbers correctly
To calculate expected value,
We can add up the probability of all possible events.
The 2 possible events are either winning $50 or losing the prize, which is $ - 50
Expected value =
50 x 40 % + (-50) x 60%
= $-10
So the answer is $-10
(sorry if it's too late and you've already figured it out, but here you go anyway)
The easiest way to do this is to start by FOILing then add.
So just start with (x-1)(x-1)
(x-1)(x-1)
Front: (x*x) = x^2
Outer: (x*-1) = -x
inner: (-1*x) = -x
Last: (-1*-1) = 1
Added: x^2 -2x +1
Now take that answer and do the same thing with (x-1). It's basically the same thing, just with an added thing you need to multiply.
(x-1)(x^2-2x+1)
(x*x^2) = x^3
(x*2x) = 2x^2
(x*1) = x
(-1*x^2) = -x^2
(-1*-2x) = 2x
(-1*1) = -1
Now add everything together:
x^3+2x^2+x-x^2+2x-1
The answer is:
x^3+x^2+3x-1
