A. Will the sum of 2x3+x2–4 and –5x3–6x2 be a polynomial? B. How do you know
polynomials...
-not closed under subtraction
-are closed under addition
- are not closed under addition
- are closed under subraration
PLZZ HELP I NEED THIS FAST AND I PUT THE POINTS REALLY HIGH

Gabriel determined that his total cost would be represented by 2.5x + 2y – 2. his sister states that the expression should be x + x + 0.5x + y + y – 2. who is correct? explain.

Will mark determine whether the conjecture is true or false. give a counterexample for any false conjecture. given: points r, s, and t conjecture: r, s, and t are coplanar. a) false; the points do not have to be in a straight line. b) true c) false; the points to not have to form right angles. d) false; one point may not be between the other two.

The length of a rectangular plot of land is given by the expression 6x^3y^4. the width of the plot is given by the expression 5x^5y^4z. find an expression to represent the area of the rectangular plot.