The difference of the square of x and the sum of nine and x

Cam bought some used books for $4.95. he paid $0.50 each for some books and $0.35 each for the others. he bought fewer than 8 books at each price. how many books did cam buy?

The sum of the first eight terms of an arithmetic progression is 9m + 14. the fifth term of the06 progression is 2m - 6, where m is a constant.given that the first term of the progression is 26,find the value of the common difference, d and thevalue of m.

Asalesperson has january sales of $20,000(1,$20,000) and april sales of $80,000 (4,$80,000). what is the rate of change?