E^2x -2e^x -8=0 => e<span>^(2x) -2e^x -8=0
Temporarily replace e^x with y.
Then (y)^2 - 2y - 8 = 0. Factors are (y-4) and (y+2).
Roots are y = 4 and y= -2.
Now remembering that we temporarily replaced e^x with y, we let
y=4 = e^x. We need to solve for x. Taking the natural log of both sides, we get:
ln 4 = x (answer)
We have to discard the other root (y= -2), because we cannot take the ln of a negative number.
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First, we need to know the smallest two digit prime number. It can't start with one, since one is not prime, so it must start with two (or be in the twenties.) 20 is divisible by 2, 4, 5, and 10, 21 is divisible by 7 and 3, 22 is divisible by 2 and 11, so the smallest prime number is 23.
Now we need the largest two-digit prime number. It cannot start with nine or eight, since both are composite, so it must start with seven (be in the seventies.) 79 is the largest integer in the seventies and also happens to be prime, so there's our largest two digit prime number.
now we just need to add them for the sum:
23+79=102
hope I helped, and let me know if you have any questions :D
Step-by-step explanation:
You can set up a proportion.
Let x be the number of pencils needed.
Solve for x.
x = 9444.44 pencils (round it up to 9445 pencils if you need a whole number)
Step-by-step explanation:
1. 5/8 = 62.5%
2. 1/5 = 20%
3. 4 2/3 = 4.66%
