12 (0.2X^)^3-(0.3X^3)^2
13 (2a^2X^4)^3-(2a^3X^6)^2
14 [-(x^y)^3]^3
15 (a^n * b^n+1)^3 *ab
16 (-x)^*x^3*(-2y)^3+2xy)^*(-x)^3
17 2^10*(-0.25)^6
18 (3/4)^50*(4/3x^3)^50
19 已知x^n=5,求(3x^3n)^2-4(x^)^2n
12 (0.2X^)^3-(0.3X^3)^2
13 (2a^2X^4)^3-(2a^3X^6)^2
14 [-(x^y)^3]^3
15 (a^n * b^n+1)^3 *ab
16 (-x)^*x^3*(-2y)^3+2xy)^*(-x)^3
17 2^10*(-0.25)^6
18 (3/4)^50*(4/3x^3)^50
19 已知x^n=5,求(3x^3n)^2-4(x^)^2n