Find the coefficient of x^4 in the expansion of (2x+5)^k

Find the average speed of a rabbit that runs a distance of 22 m in a time of 1.8 s .

Elena and her husband marc both drive to work. elena's car has a current mileage (total distance driven) of 15,000 and she drives 23,000 miles more each year. marc's car has a current mileage of 46,000 and he drives 9,000 miles more each year. will the mileages for the two cars ever be equal? explain.

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form