The goal to proving identities is to transform one side into the other. We can only pick one side to transform while the other side stays the same the entire time. The general rule of thumb is to transform the more complicated side (though there may be exceptions to this guideline).
So I'll take the left hand side and try to turn it into 
One way we can do that is through the following steps:

Since we've shown that the left hand side transforms into the right hand side, this verifies the equation is an identity.
9514 1404 393
Answer:
- straight time: $699.20
- overtime: $165.60
- total pay: $864.80
Step-by-step explanation:
(a) Maria's straight time pay is ...
(38 h)×($18.40 /h) = $699.20
__
(b) Maria's overtime pay is ...
(6 h)×(1.5×$18.40 /h) = $165.60
__
(c) Her total pay is the sum of her straight time pay and her overtime pay:
$699.20 +165.60 = $864.80
Answer:
Actually, what you said you have so far is not correct. The 2 correct answers are the 1st one (x + y = 15) and the 5th one (15x + 10y > 180)
Step-by-step explanation:
If tutoring French is x hours and scooping ice cream is y hours and he is going to work 15 hours for sure doing both, then we can add them together to get that x hours + y hours = 15 hours, or put simply: x + y = 15.
Now we are going to throw in the added fun of the money he makes doing each. The thing to realize here is that we can only add like terms. So looking at the equation above, we have x hours of tutoring and y hours of scooping, so if we want to add them, we will add those number of hours together to get the total number of hours he worked, which we know to be 15. The same goes for money. If we add money earned from tutoring to money earned from scooping, we need that to be greater than the money he wants to earn which is 180 at least. Because he wants to earn MORE than $180. we use the ">" sign. Since he earns $15 an hour tutoring, that expression is $15x; since he earns $10 an hour scooping, that expression is $10y. Now add them together (and you CAN because they are both expressions relating dollars to dollars) and set the sum > $180:
$15x + $10y > $180. That's why your answer is not correct. Use mine (with the understanding that you care about why yours is wrong and mine is correct) and you'll be fine.
Answer:
Mean = 30516.67
Standard deviation, s = 3996.55
P(x < 27000) = 0.0011518
Step-by-step explanation:
Given the data:
28500 35500 32600 36000 34000 25700 27500 29000 24600 31500 34500 26800
Mean, xbar = Σx / n = 366200 /12 = 30516.67
Standard deviation, s = [√Σ(x - xbar) / n-1]
Using calculator, s = 3996.55
The ZSCORE = (x - mean) / s/√n
Zscore = (27000 - 30516.67) / (3996.55/√12)
Zscore = - 3516.67 / 1153.7046
Zscore = - 3.048
P(x < 27000) = P(Z < - 3.049) = 0.0011518