Question

Объясните как решать?

Answer 1

$\frac{a-b}{2+c}=\frac{4,2-(-4,3)}{2+(-5,4)}=\frac{4,2+4,3}{2-5,4}=\frac{8,5}{-3,4}=-2,5\\\\Otvet:\boxed{-2,5}$

Answer 2

$\displaystyle \tt \frac{a-b}{2+c}=\frac{4,2-(-4,3)}{2+(-5,4)}=\frac{4,2+4,3}{2-5,4}=-\frac{8,5}{5,4-2}=-\frac{8,5}{3,4}=-2,5;$