How to solve through elimination the following 2m=-4n-4 and 3m+5n=-3

A) if $50000 is invested in a bank account that pays 9.3% of interest compounded on a six-monthly basis, how much money will be in the account after 3 and 12 years? b) if matusalen's father had put $2.0 in the bank when he was born and there, how long would matusalen have had to his death (969 years later) if the interest was 7% per year composed each month and weekly?

Empty box + box + empty box fill in the box is equal to 30 how

Ineed in figuring out this problem.