I would look at this as a percent. 23/25 is 92%. To find the percent of a number, make the percent a decimal and multiply. 2,540 times 0.92 is 2,336.8, so therefore the Mississippi is 2,336.8 miles long.
The answer is A) 4.7x²+1.6x+3.27.
When adding the polynomials, we combine like terms:
2.3x²+2.4x² = 4.7x²
-5.6x+7.2x = 1.6x
2.3+0.97 = 3.27