** ATTENTION ** HELP PLEASE (Will give brainlist)

Which of the following equations demonstrate that the set of polynomials is not closed under the certain operations?

A. Multiplication. (3x^4+x^3)(-2x^4+x^3)=-6x^8+x^7+x^6

B. Addition: (3x^4+x^3)+(-2x^4+x^2x^4+2x^2

C. Division: (x^2+2x_+(x+1)=x+x/x+1

D. Multiplication: (x^2+2x)(x+1)=x^3+3x^2+2x

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this

quit

step-by-step explanation:

34

step-by-step explanation:

step-by-step explanation:

*calories burned = (weight)(calorie factor)*

calories burned = 180 (0.65)

calories burned = 117

the calories he used up is 117, which is 65% of his weight.