Ax^2 + bx + c is a quadratic trinomial. Therefore, ur expression is a quadratic trinomial......it is a trinomial because it has 3 terms.....quadratic means the highest exponent is 2.
Our P = 100, r = .08, n = 1 (annually means once a year), and t = 15. Filling in accordingly, we have

. Simplifying a bit gives us

and

. Raising that number inside the parenthesis to the 15th power gives us

. Multiplying to finish means that A(t) = $317.22
4x^2-25= (2x)^2-5^2=(2x-5)(2x+5)
Used: a^2-b^2=(a+b)(a-b)
I got C for 6 & 7. I haven't done this in a while so I don't know 8 & 9. I hope I helped!