Plz help me, 6th-grade math

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?

Solve this equation using substitution. {4x + y = −2} {4x + 6y = 44}

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)