PLEASE HELP, u will get What would be an algebraic equation to show how many marbles could fill up the jar? The jar is 15 cm

3 # of marbles, x 6.9cm height of water, Y
5 # of marbles, x 7.5cm height of water, Y
9 # of marbles, x 8.7cm height of water, Y
14 # of marbles, x 10.2cm height of water, Y
17 # of marbles, x 11.1cm height of water, Y
23 # of marbles, x 12.9cm height of water, Y