90720^2=8230118400
3x2 + 36x + 81 = 3(x2 + 13x + 27)
3x2 + 36x + 81 = 3(x2 + 12x + 27) = 3(x + 3)(x + 9), which are its prime factors; or, if you prefer, 3x2 + 36x + 81 = (3x + 9)(x + 9), which is also accurate. You may easily verify these results by multiplying back.
The square root of (36x)8 = (36x)4 The square root of 36x8 = 6x4
(3X + 9) (X + 9)
(√4x^2)(√36x)=2x(6√x)=12x√x
6x
If you mean: 9x2-36x+16 then it is not a perfect square because its discriminant is greater than zero
√36x^3 = √(6^2)(x^2)x =6x√x
9x4
Some signs would have made life easier at this end. (3x + 9)(x + 9) is a possibility, as is (3x - 9)(x - 9)
square root of 420 is 20.4939015 or 2sqrt(105)
Multiply the two dimensions to get the area. The calculation will give you 2,160 square feet.