Ialready solved this problem. i just need with the hint part.
the sum of two numbers is 25 and the sum of their squares is 313. find the number. (hint: let one of the numbers be x. express the other number in terms of x.)

2/3(-6y+9x) expand each expression using the distributive property

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)

You have 37 coins that are nickels, dimes, and pennies. the total value of the coins is $1.55. there are twice as many pennies as dimes. find the number of each type of coin in the bank.