Which expression is equivalent to x^4 - 12x^2 + 36?

(1) (x^2 - 6) (^x2 - 6) (3) (6 - x^2) (6 + x^2)

(2) (x^2 + 6) (x^2 + 6) (4) (x^2 + 6) (x^2 - 6)

So the answer is

(x^2 plus or minus 6) (x^2 plus or minus 6)

an easy way to do this is to only look at plus or minus 6

x^4 - 12x^2 + 36 (-12 and 36)

6 x 6 = 36

6 + 6 ≠ - 12 (x^2 + 6) (x^2 + 6) is incorrect

6 x - 6 ≠ 36

6 + - 6 ≠ - 12 (x^2 - 6) (x^2 + 6) is incorrect

-6 x - 6 = 36

-6 + - 6 = - 12 (x^2 - 6) (x^2 - 6) is correct

the answer is (1)