x^2+6xy+9y^2分之2x+6y乘以x分之x^2-9y^2化简求值

问题描述:

x^2+6xy+9y^2分之2x+6y乘以x分之x^2-9y^2化简求值

(2x+6y)/(x^2+6xy+9y^2) *(x^2-9y^2)/x
=2(x+3y)/(x+3y)^2* (x+3y)(x-3y)/x
=2(x-3y)/x