Find the value of x.

Answer this question! 30 points and brainliest! only if you know the answer.

100 points, hi, i’m not sure what to do here, the data doesn’t seem to be quadratic .? can anyone me, in advance

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?