Answer:
-150
Step-by-step explanation:
x^2 - 7x^2 - 18x +42
3^2 - 7(3)^2 - 18(3) + 42
9 - 63 - 54 + 42
-54 -54 + 42
-108 + 42
-150
Answer:
a) 0.4567
b) 6 hours
Step-by-step explanation:
We are given the following information the question:
The battery life follows a normal distribution with

Formula:

a) We have to find probability such that battery life exceeds 10 hours, that is,
P(X>10)

b) We have to find battery life such that

Here, we calculated the value of z from the normal distribution table.
So, after approximately 6 hours one should plan to recharge the phone.
Answer:
6/7
Step-by-step explanation:
6/7 is not an integer. Integers are {..., -3, -2, -1, 0, 1, 2, 3, ...}.