Answer:
2.25
Step-by-step explanation:
The total frequency is:
20 + 12 + 6 + 2 = 40
Calculate the probability of each score:
P(X=3) = 20/40 = 0.50
P(X=2) = 12/40 = 0.30
P(X=1) = 6/40 = 0.15
P(X=0) = 2/40 = 0.05
So the expected value is:
E = (3)(0.50) + (2)(0.30) + (1)(0.15) + (0)(0.05)
E = 2.25
Use completion of sq method
x^2+y^2+14x+10y-7=0
(x+7)^2+(y+5)^2=7+49+25
(x+7)^2+(y+5)^2=81
so centre is(-7,-5) radius is9
800(1+7)∧4
it will be $1048.63
The expression will be x-3.
