What are the x-intercepts of the functions fx)=-4(x+3)(x-9) ?
1 answer:
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Answer:
a) see below
b) 40x20 meters
Step-by-step explanation:
Write down what you know:
- The area of the enclosure is length*width, so
- The length of the fencing is 80 meters, so
Now we have to combine these two equations above, and get rid of y in the process.
First rewrite the second as:
Then substitute for y in the first:
b) To maximize A, find the zero of the first derivative:
So y = (80-40)/2 = 20 meters.
For this case we have the following data:
So that the figure can be a rectangle, its diagonals must be equal, that is,
In this way we have:
Clearing x we have:
Thus, x must be equal to 10 so that the figure is a rectangle.
Answer:
Option A