指數記數法!!-

a^3*a^6/a^4=a^9/a^4=a^5
因為a^3*a^6=(a*a*a)*(a*a*a*a*a*a)=(a*a*a*a*a*a*a*a*a)=a^9
而a^9/a^4=(a*a*a*a*a*a*a*a*a)/(a*a*a*a)=(a*a*a*a*a)=a^5
(21^2)^3/a*2a^3=21^6/2a^4
因為(21^2)^3=(21^2)*(21^2)*(21^2)=(21*21)*(21*21)*(21*21)=21^6
而a*2a^3=a*2*a^3=a*2*a*a*a=2a^4
(3ab^2)^3=3^3*a^3*b^6
因為(3ab^2)^3=(3ab^2)*(3ab^2)*(3ab^2)=3*3*3*a*a*a*b*b*b*b*b*b=3^3*a^3*b^6

a^3*a^6/a^4

=a^9/a^4

=a^5

(2a^2)^3/a*2a^3

=2^3/a*2a

=2^3/2a^2

=2^2/a^2

(3ab^2)^3

=9a^3b^6

a^3*a^6/a^4
=a^3+6-4
=a^5

(21^2)^3/a*2a^3 *r唔知係你抄錯題掟係我蠢= ="

(3ab^2)^3
=9ab^6

1.a3*a6*a4
=a^3+6+4
=a^13

2. (21^2)3/2a*a3
=21^6/2a*a^3
=85766121/a(2*a^2)

3.(3ab^2)^3
=3^3*a^3*b^6
=27*a^3*b^6