It has been awhile since I worked with in qualities but I got the answer,
-1/3 < or equal to p < or equal to 2.
I multiplied the 5 in the middle of the equation with what's in parentheses to get 15p - 10, then I added 10 to both outer sides of the equation and got
-5 < or equal to 15p < or equal to 30.
Then lastly I divided 15 by -5 and 30!
I hope that's right.. I'm sorry if it isn't!
Answer:
a) 0.216
b) 0.1587
c) 0.369
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 12.2 grams
Standard Deviation, σ = 2.8 grams
We are given that the distribution of weights of impurities per bag is a bell shaped distribution that is a normal distribution.
Formula:
a) P(contains less than 10 grams of impurities)
P(x < 10)
Calculation the value from standard normal z table, we have,

b) P(contains more than 15 grams of impurities)
P(x > 15)
Calculation the value from standard normal z table, we have,

c) P(contains between 12 and 15 grams of impurities)

d) The mean divide the data in exactly two parts. Since 15 is farther away from the mean as compared to 10, the probability obtained in part (b) is smaller as compared to probability obtained in part (a).
Let's solve your equation step-by-step:
x^2+6x-16=0
Factor the left side of the equation:(x-2)(x+8)=0
Set factors equal to 0: x-2=0 or x+8=0, x=2 or x=-8
Your answer is x=2 or x=-8, doesn't matter which, both are correct.
Hope this helps!:)