Let P=Perm cost
Let H = Haircut cost
Let L = Lunch cost
Perm costs twice as much as haircut so.. P = 2H
L = 5
H + P + L = 68 the total cost is $68
H + 2H + 5 = 68 since P = 2H and L=5
3H + 5 = 68
3H =63
H = 63/3
H = 21
A Haircut is $21
Perm = 2H = 2(21) = $42
For a given function, slope is defined as the change in outputs, or y-values divided by the change in inputs, or x-values. In essence the slope asks "For a given change in x, how much does y change?" or even more simply: "How steep is the graph of this function?". This can be represented mathematically by the formula:

Since we have a table of x,y pairs it's the last form of that equation that will be the most useful to us. To compute the slope we can use any two pairs, say the first two, and plug them into our formula:

We can check this answer by using a different pair, say the last two:

.
As a common sense check: Our y-values get smaller as our x-values get bigger so a negative slope makes sense.
m=-3
Answer:
C
Step-by-step explanation:
Since y will have same value, y doesn't really matter. Thus,
We can solve for y in the 2nd equation as:
-3x - y = 4
-3x - 4 = y
Now we can plug it into the first and solve for x:
-9x + 4y = 8
-9x + 4(-3x - 4) = 8
-9x - 12x - 16 = 8
-21x = 8 + 16
-21x = 24
x = 24/-21
x = -8/7
Correct answer is C.
Answer:
c
Step-by-step explanation:
.............,.......... confused with a and c
The 68-95-99.7 rule tells us 68% of the probability is between -1 standard deviation and +1 standard deviation from the mean. So we expect 75% corresponds to slightly more than 1 standard deviation.
Usually the unit normal tables don't report the area between -σ and σ but instead a cumulative probability, the area between -∞ and σ. 75% corresponds to 37.5% in each half so a cumulative probability of 50%+37.5%=87.5%. We look that up in the normal table and get σ=1.15.
So we expect 75% of normally distributed data to fall within μ-1.15σ and μ+1.15σ
That's 288.6 - 1.15(21.2) to 288.6 + 1.15(21.2)
Answer: 264.22 to 312.98