(x^2-9)(x^2+9)-(9-x^2)^2_数学解答

(x^2-9)(x^2+9)-(9-x^2)^2

人气：218 ℃　时间：2020-02-05 19:47:39

解答

(x²-9)(x²+9)-(9-x²)²
＝(x²-9)(x²+9)-(x²-9) ²
=(x²-9)[x²+9-(x²-9)]
=(x²-9)(x²+9-x²+9)
=18(x²-9)
=18(x+3)(x-3)