[tex](n-1)-4= \frac{25}{10} = n = \frac{15}{2} [/tex]
Espero que esteja certa!!
(n-1)-4= 25
10
-4n +4 = 25
10 tire o mmc
-40n + 40 = 25
-40n = 25-40
-40n = - 15
-n = -15
40
n = 15:5
40:5
n = 3
8
