2(x+7) + x=20
(2)(x) + (2)(7) + x=20 Distribute
2x+14 + x =20
(2x+x) + (14) =20 Combine Like Terms
3x+14=20
- 14 -14 Subtract 14 from both sides
3x = 6
3x/3 6/3 Divide Both Sides by 3
x = 2
Let me know if you still don't understand
Answer:
a) Y(x) = {900, x≤30; 900-40(x-30), x>30}
b) T(x) = {900x, x≤30; 2100x-40x², x>30}
c) dT/dx = {900, x≤30; 2100-80x, x>30}
Step-by-step explanation:
a) The problem statement gives the function for x ≤ 30, and gives an example of evaluating the function for x = 35. So, replacing 35 in the example with x gives the function definition for x > 30.
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b) The yield per acre is the product of the number of trees and the yield per tree:
T(x) = x·Y(x)
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c) The derivative is ...
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The attached graph shows the yield per acre (purple, overlaid by red for x<30), the total yield (black), and the derivative of the total yield (red). You will note the discontinuity in the derivative at x=30, where adding one more tree per acre suddenly makes the rate of change of yield be negative.
There is no picture here. Do you have a picture i can use to better understand the question?
Answer:
On my calculator it appears as 0.7 recurring
1. First, let us define the width of the rectangle as w and the length as l.
2. Now, given that the length of the rectangle is 6 in. more than the width, we can write this out as:
l = w + 6
3. The formula for the perimeter of a rectangle is P = 2w + 2l. We know that the perimeter of the rectangle in the problem is 24 in. so we can rewrite this as:
24 = 2w + 2l
4. Given that we know that l = w + 6, we can substitute this into the formula for the perimeter above so that we will have only one variable to solve for. Thus:
24 = 2w + 2l
if l = w + 6, then: 24 = 2w + 2(w + 6)
24 = 2w + 2w + 12 (Expand 2(w + 6) )
24 = 4w + 12
12 = 4w (Subtract 12 from each side)
w = 12/4 (Divide each side by 4)
w = 3 in.
5. Now that we know that the width is 3 in., we can substitute this into our formula for length that we found in 2. :
l = w + 6
l = 3 + 6
l = 9 in.
6. Therefor the rectangle has a width of 3 in. and a length of 9 in.
