Find the least common denominator for these two rational expression 4/s^2 -7/7s^2

Henry is an avid reader, he devours 90 pages in half an hour how many pages has henry read per minute?

Iam a rectangle. my perimeter is 60 feet. how much are do i cover?

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)