Question

(3/4a的四次方b的七次方+1/2a的三次方b的八次方-1/9a的平方b的六次方）÷（-1/3ab的三次方）的平方

其中a=1/2,b=-4

Answer 1

(3/4a的四次方b的七次方+1/2a的三次方b的八次方-1/9a的平方b的六次方）÷（-1/3ab³)²
=(3/4a^4b^7+1/2a^3b^8-1/9a^2b^6）÷（1/9a^2b^6)
=27/4a²b+9/2ab²-1 其中a=1/2,b=-4
=27/4*(1/2)²*(-4)+9/2*(1/2)*(-4)²-1
=-27/4+9-1
=8-27/4
=32/4-27/4
=5/4

Answer 2

原式=((3/(4a^4*b^7)+1/(2a^3*b^8)-1/(9a^2*b^6))/((-1/3ab^3)^2)
=((3/(4a^4*b^7)+1/(2a^3*b^8)-1/(9a^2*b^6))*(9a^2*b^6)
=27/(4ba^2）+9/(2ab^2)-1
将a=1/2,b=-4 代入得
原式=27/(4*(-4)*(1/2)^2)+9/(2*(1/2)*(-4)^2-1
=-27/4+9/16-1
=-115/16