DI/dx=-850x+45500
d2l/d2x=-850 so when dl/dx=0 it is an absolute maximum for l(x)...
dl/dx=0 only when:
850x=45500
x=53.53
x=54 years of age (rounded)
Answer:

Step-by-step explanation:
Use the Pythagorean Theorem:
![\displaystyle a^2 + b^2 = c^2 \\ \\ 9,7^2 + b^2 = 13,3^2; \sqrt{82,8} = \sqrt{b^2} \\ \\ \frac{3\sqrt{230}}{5}\:[or\:9,0994505329...] = b](https://tex.z-dn.net/?f=%5Cdisplaystyle%20a%5E2%20%2B%20b%5E2%20%3D%20c%5E2%20%5C%5C%20%5C%5C%209%2C7%5E2%20%2B%20b%5E2%20%3D%2013%2C3%5E2%3B%20%5Csqrt%7B82%2C8%7D%20%3D%20%5Csqrt%7Bb%5E2%7D%20%5C%5C%20%5C%5C%20%5Cfrac%7B3%5Csqrt%7B230%7D%7D%7B5%7D%5C%3A%5Bor%5C%3A9%2C0994505329...%5D%20%3D%20b)
So, you have this:

I am joyous to assist you at any time.
Square root x * square root x = square root of x^2 which is just absolute value of x which is just x.
Now you’re left with 7x square root 7
I hope this helps
Answer:
12.5%
Step-by-step explanation: