Question

已知a=2√7,b=5√2,求a^6b^-6 - 9b^4 / √a^6b^-6 - 6a^3b^-1 +9b^4 乘

Answer 1

a^6b^-6 - 9b^4 / √a^6b^-6 - 6a^3b^-1 +9b^4 乘 b^5/a^3+3b^5

=（a^3b^-3+3b^2）（a^3b^-3-3b^2）/√（a^3b^-3-3b^2）^2乘 b^5/a^3+3b^5

==（a^3b^-3+3b^2）乘 b^5/a^3+3b^5

=b^-3（a^3+3b^5）乘 b^5/a^3+3b^5

=b^2

b=5√2

式子=50