Expand the polynomial: (5/8 x + y^5)(-5/8 x - y^5)

The long jump record, in feet, at a particular school can be modeled by f(x) = 19.6 + 2.5ln(x + 1) where x is the number of years since records began to be kept at the school. what is the record for the long jump 11 years after record started being kept? round your answer to the nearest tenth.

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years