The answer is D, because -2/3/2 = -4/3.
Answer:
1250 m²
Step-by-step explanation:
Let x and y denote the sides of the rectangular research plot.
Thus, area is;
A = xy
Now, we are told that end of the plot already has an erected wall. This means we are left with 3 sides to work with.
Thus, if y is the erected wall, and we are using 100m wire for the remaining sides, it means;
2x + y = 100
Thus, y = 100 - 2x
Since A = xy
We have; A = x(100 - 2x)
A = 100x - 2x²
At maximum area, dA/dx = 0.thus;
dA/dx = 100 - 4x
-4x + 100 = 0
4x = 100
x = 100/4
x = 25
Let's confirm if it is maximum from d²A/dx²
d²A/dx² = -4. This is less than 0 and thus it's maximum.
Let's plug in 25 for x in the area equation;
A_max = 25(100 - 2(25))
A_max = 1250 m²
Answer:
B.
Step-by-step explanation:
she only has $60 to spend therefore, she has the option of spending all of it, or less. However she cannot spend money she doesn't have.
Use substitution.
2p + 3(2p) = 680
2p + 6p = 680
8p = 680
p = 85
Plug in.
x = 2p
x = 2(85)
x = 170
p = 85
Answer:
cost = 1.35n
$33.75 for 25 songs
Step-by-step explanation:
Based on the numbers given, the cost is proportional to the number of songs downloaded. The constant of proportionality is the cost of one song: 1.35.
cost = 1.35n
For 25 songs, ...
cost = 1.35·25 = 33.75 . . . . dollars
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The equation is ...
cost = 1.35n
