Question

b^2-4b/b^2-16 при b =-9

Answer 1

$frac{b^2-4b}{b^2-16}=frac{b(b-4)}{(b-4)(b+4)}=frac{b}{b+4}$

при b=-9

$frac{-9}{-9+4}=frac{-9}{-5}=1,8$