Please help me! My teachers haven't taught me this yet and I'm freaking out!

Simplify the polynomial.

-3f^2+4f-3+8f^2+7f+1

A. 5f^2-11f+2
B. 11f^2+11f+2
C. 5f^2+11f-2
D. -5f^2+11f-2

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?