Объяснение:
(x²-4x)/(x²+7x)=x*(x-4)/(x*(x+7)=(x-4)/(x+7).
(24-6x)/(49-x²)=6*(4-x)/((7-x)(7+x)) ⇒
((x-4)/(x+7))*(7-x)*(x+7)/(6*(4-x))=(x-4)(x+7)(7-x)/((x+7)(6*(4-x))=
=(x-4)(7-x)/(6*(4-x))=(x-4)(7-x)/(-(6*(x-4))=(7-x)/(-6)=(x-7)/6.
