1/(6X-4Y)-1/(6X+4Y)+3X/(4Y^2-9X^2)=

问题描述:

1/(6X-4Y)-1/(6X+4Y)+3X/(4Y^2-9X^2)=

(6X+4Y)/(36X2-16Y2)-(6X-4Y)/(36X2-16Y2)=2Y/(9X2-4Y2)
再+3X/(4Y^2-9X^2)
=(2Y-3X)/(4Y^2-9X^2)=2Y+3X