2.4n - 3 and -7.8n + 2

i'm confused pls explain

Which of the following statement about pascal's triangle are true?

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?

What is the solution to this system of equations? y= 2x - 3.5 x - 2y = -14