D. 129pi cm^squared
this is the answer that was cut off

 OPTION C

Step-by-step explanation:

The formula for calculate the surface area of a cone is shown below:

Where r is the radius, l is the slant height and SA is the surface area of the cone.

Substitute the values into the formula shown above. Therfore, the surface area of the cone is:

 cm²

t = 3

step-by-step explanation:

put t = 3 in this expression :

(3²-1)(3²-2)(3² - 3)(3² - 4) = 8×7×6×5 = 56×30 = 1680

let m = monomial

let t = trinomial

so, m times t = t.

monomial times a trinomial = another trinomial.