What is the answer and i need work for both parts !

Diane’s bank is offering 5% interest, compounded monthly. if diane invests $10,500 and wants $20,000 when she withdrawals, how long should she keep her money in for? round to the nearest tenth of a year.

Yvaries directly as x. y =90 when x=6. find y when x=13

What is the distance between (5 - 2i) and (8 + i)?