Need help in math pre algebra

What is the 9th term in the geometric sequence described by this explicit formula? an=-6. (2)(n-1) apex

Tim open up a new saving account with a $50 deposit and plant to deposit $20 per week into the same account.write an expression to represent the total amount in his savings account.

Which polynomial is in standard form? 3xy+6x®y2 - 4x4y + 19x? y* 18x5 - 7x{y-2xy2 + 1774 x5y5 - 3xy - 11x? y2 +12 15+ 12xy2 - 11x®ys +5x? y2 ?