Rectangular prism...becuase it is in rectangular shape..no matter how you cut it..it will give u a rectangle
If a binomial

is a factor of a polynomial, then

is a root of this polynomial.
When you have something like this, all you need to do is substitute the values, the last is for what value of x
For the first one;
((x^2+1)+(x-2))(2)
(x^2+x-1)(2)
(2)^2+(2)-1
4+2-1
5
For the second one;
((x^2+1)-(x-2))(3)
(x^2-x+3)(3)
(3)^2-(3)+3
9-3+3
9
For the last one;
3(x^2+1)(7)+2(x-2)(3)
3((7)^2+7)+2((3)-2)
3(49+7)+2(3-2)
3(56)+2(1)
168+2
170
Circumference of a circle = 2 x pi x radius
C = 2 x pi x 3
C = 6 x pi
C = 18.84
(using 3.14 for pi)