Plz help me well mark brainliest if correct

The interior angles formed by the side of a hexagon have measures of them up to 720° what is the measure of angle a

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

Select the correct answer from each drop-down menu. consider the following polynomials equations. 3x^2(x-1) and -3x^3+ 4x^2-2x+1 perform each operation and determine if the result is a polynomial. is the result of a + b a polynomial? yes or no is the result of a - b a polynomial? yes or no is the result of a · b a polynomial? yes or no