Is 4.9² a rational number

no... it's not

A. polynomials is standard form are written with their degrees arranged from left to right (highest degree to lowest degree)example: 4x^4+ 2x^3 + 6x^2 + 5x -7b. the closure property means that they are closed in addition, subtraction just like integers. i.e. their degrees dont change under addition and subtraction example: (3x^3 + 4x ) + (6x^4 - x)= 3x^3 + 4x + 6x^4 - x= 3x^3 + 3x + 6x^4