Find all relative extrema of the function. Use the Second Derivative Test where applicable. f(x) = x6/7 − 9

If 20% of a number is 35, what is 50% of that number?

How do you solve a question like this?

Ametal rod needs to be 9 feet and 5.5 inches in length. the sections of the poles being used are each 1 foot and 10.5 inches long. how many 1ft 10.5in sections would be needed to complete the 9ft 5.5in metal rod? and how many inches of material will be left?