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
