How do I solve this: 1/2x1 + 1/2x3 + 1/4x3 ... + 1/n(n-1)

Find the length of the following tangent segments to the circles centered at o and o' whose radii are 5 and 3 respectively and the distance between o and o' is 12. what is the tangent segment of cd?

Which of the following is the equation that says that the product of a number and ten is equal to 20 percent of that number ? a) 10n= 2.0n b) 10+n=.20n c) n+ .20n=10 d) 10n=0.20n

If f(x)= 3x+6 which of the following is the inverse of f(x)