Помогите, пожалуйста.

[-(c³+7c²)/2b]÷(49-c²)/4b²=-4b²c²(c+7)/2b(7²-c²)=-2bc²(7+c)÷(7-c)(7+c)=

-2bc²/(7-c)=2bc²/(c-7)

2)(.3m-6n/m··n)÷(m²-4mn+4n²)=3(m-2n)/m·n÷(m-2n)²=3/m·n(m-2n)
3)(2x-6/2x+6)÷(9-x²/x²+6x+9)=2(x-3)(x+3)²/2(x+3)(3-x)(3+x)=2(x-3)/2(3-x)=-1