Answer:
The original number could be 85.
Step-by-step explanation:
Let the 2 digits be x and y.
Let the number be xy then, assuming that x is the larger digit:
x - y = 3.
x = y + 3
Also
10y + x + 10x + y = 143
Substituting for x:
10y + y + 3 + 10(y + 3) + y = 143
22y + 33 = 143
22y = 110
y = 5.
So x = y + 3 = 8.
I would say the best estimate would be 9 because the real answer is 8.71 and if you round that to the 1 place the answer would be 9.
bro where is the pic???? how are we supposed to answer this?
(a) First find the intersections of
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and
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:
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So the area of
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is given by
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If you're not familiar with the error function
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, then you will not be able to find an exact answer. Fortunately, I see this is a question on a calculator based exam, so you can use whatever built-in function you have on your calculator to evaluate the integral. You should get something around 0.5141.
(b) Find the intersections of the line
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with
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.

So the area of
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is given by
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
which is approximately 1.546.
(c) The easiest method for finding the volume of the solid of revolution is via the disk method. Each cross-section of the solid is a circle with radius perpendicular to the x-axis, determined by the vertical distance from the curve
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and the line
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, or
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. The area of any such circle is
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times the square of its radius. Since the curve intersects the axis of revolution at

and

, the volume would be given by