Find the equivalent expression using the same bases (21•15)^9

Yuri, sam and dani had the same math homework last night, but none of them finished it. yuri finished 3/8 of her homework, sam finished 4/6 of her homework and dani finished 1/2. who finished the most math homework? who finished the least amount?

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?

Anature center offer 2 guided walks. the morning walk is 2/3 miles. the evening walk is 3/6 mile. which is shorter