Answer:
p=0 or p=-7/15
Step-by-step explanation:
15p2+7p=0
p(15p+7)=0
p=0 or 15p+7=0
Answer with explanation:
The given expression is

→As, multiplication of real number follows Commutative property.
Which states that, if a and b are any two real numbers , then
a × b= b × a
The Expression equivalent to ,the above expression are

Answer:
Expected time is 15 hours for him to get to safety.
Step-by-step explanation:
We define X as the time that this miner would get to safety.
We define Y as the door he chooses initially.
P(Y= 1) = P(Y=2)=P(Y=3) = 1/3
We have E[X|Y=1] = 3
E[X|Y] = 5 hours + E[X}
E[X|Y] = 7 hours + E[X]
Then we have
E[X] = 1/3(3 + 5 + E[X] + 7 + E[X])
We cross multiply
3*E[X] = (15 + 2E[x])
3E[X] - 2E[X] = 15
E[X] = 15
So the time it would take to get him to safety is 15 hours
Differnce of 2 pefect squares
a^2-b^2=(a-b)(a+b)
(p^2)^2-9^2=(p^2-9)(p^2+9)
p^2-9=(p-3)(p+3)
factored is
(p-3)(p+3)(p^2+9)
D is under multiplication