Add a photo. this is confusing
The data is a little bit complex,but you can use the knowledge of vector in the subject of algebra,or you can ultimate the basic Euclidean knowledge,like cosine theorem.In detail,you can list two equation with two variable,and get the answer.but i don't finish calculating it.
Answer:
u = 3
Step-by-step explanation:

I hope I've helped you.
The best and most correct answer among the choices provided by your question is the fourth option or letter D. The expression that represents Graham's sales is 2a − 6. Twice the sales of Adrianne, deducted by 6 should be Graham's sales.
Hope this helps!
Answer:
0.3085 = 30.85% probability that a randomly selected pill contains at least 500 mg of minerals
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean
and standard deviation
, the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean 490 mg and variance of 400.
This means that 
What is the probability that a randomly selected pill contains at least 500 mg of minerals?
This is 1 subtracted by the p-value of Z when X = 500. So



has a p-value of 0.6915.
1 - 0.6915 = 0.3085
0.3085 = 30.85% probability that a randomly selected pill contains at least 500 mg of minerals