Question

X+3 supra 31- 15 supra 31 = 19 supra 31, aflati x

Answer 1

(x+3)/31-15/31=19/31
(x+3-15)/31=19/31
x-12=19
x=31

Answer 2

$\frac{x+3}{31}$ - $\frac{15}{31}$ = $\frac{19}{31}$ <=>
eliminam numitorul deoarece este comun si obtinem:
x+3-15=19 <=>
x-12=19 <=>
x= 19+12 <=>
x=31