Answer:
The average rate of movement along the San Andreas Fault is between 30mm and 50mm per year over the last 10 million years. If current rates of movement are maintained Los Angeles will be adjacent to San Francisco in approximately 20 million years.
Step-by-step explanation:
11+4=15-4=11
So a=11 I think so am not sure
Basic properties that will be used:

![x^{1/n}=\sqrt[n]x](https://tex.z-dn.net/?f=x%5E%7B1%2Fn%7D%3D%5Csqrt%5Bn%5Dx)

All of these expression can be written to match on or more of the patterns above.
![19.\quad\log_5\sqrt[4]{25}=\log_5(5^2)^{1/4}=\dfrac14\log_55^2=\dfrac12\log_55=\dfrac12](https://tex.z-dn.net/?f=19.%5Cquad%5Clog_5%5Csqrt%5B4%5D%7B25%7D%3D%5Clog_5%285%5E2%29%5E%7B1%2F4%7D%3D%5Cdfrac14%5Clog_55%5E2%3D%5Cdfrac12%5Clog_55%3D%5Cdfrac12)



![27.\quad\log_3\sqrt[6]{243}=\log_3(3^5)^{1/6}=\dfrac16\log_33^5=\dfrac56\log_33=\dfrac56](https://tex.z-dn.net/?f=27.%5Cquad%5Clog_3%5Csqrt%5B6%5D%7B243%7D%3D%5Clog_3%283%5E5%29%5E%7B1%2F6%7D%3D%5Cdfrac16%5Clog_33%5E5%3D%5Cdfrac56%5Clog_33%3D%5Cdfrac56)
See the picture for all detail, I have done it by hand.
Few important steps;
-Take the first derivative
-Put it equal to zero
-you get the x value which is equal to 11
-Now for the check that x=11 is the least value or not, take the second derivative
-As, the 2nd derivative is positive so it is the least value
As x=0 in 1964 add 11 to it so at
x=11 we get 1975 so in this year car have least value
2) 849= 850
4) 27= 30
8) 93= 90
10) 861= 860
12) 16= 20