用因式分解做 3ax^2-3ay^2 2x^3-8x -9x^2y+y x^4-16 2x^4-2 我还不是很会

题目

用因式分解做 3ax^2-3ay^2 2x^3-8x -9x^2y+y x^4-16 2x^4-2 我还不是很会
①3ax^2-3ay^2
②2x^3-8x
③-9x^2y+y
④x^4-16
⑤2x^4-2

答案

3ax²-3ay²
=3a(x²-y²)
=3a(x+y)(x-y)
2x³-8x
=2x(x²-4)
=2x(x+2)(x-2)
-9x²y+y
=-y(9x²-1)
=-y(3x+1)(3x-1)
x^4-16
=(x²+4)(x²-4)
=(x²+4)(x+2)(x-2)
2x^4-2
=2(x^4-1)
=2(x²+1)(x²-1)
=2(x²+1)(x+1)(x-1)