State each sum as the fraction of whole number in lowest term. 9/1*8 + 9/8*15 + 9/15*22 + ...+9/n(n+7)?
The radio telescope has the parabolic surface. If it is 1m deep and 8m wide, how far is focus from vertex?
Determine partial-fraction decomposition of 6x+1/(3x+1)^2.