[tex](24t+3):3 = \frac{24t}{3}+\frac{3}{3} = \boxed8} \ t+\boxed{1}[/tex]
[tex]-\frac{6a-4,5}{3} =\frac{-6a}{3}-(\frac{-4,5}{3}) = \frac{-6a}{3}+\frac{4,5}{3} = \boxed{-2} \ a+\boxed{1,5}[/tex]
[tex]-10\cdot\frac{y+15}{-5} = \frac{-10}{-5}\cdot(y+15) = 2\cdot(y+15) = \boxed{2} \ y + \boxed{30}[/tex]
[tex]\frac{x+15}{-20}\cdot4 =\frac{x+15}{-5} = \boxed{-\frac{1}{5}} \ x -\boxed{3}[/tex]