5 supra 12=26 supra 15-x-19 supra 60

Răspuns :

5/12=26/15-x-19/60
5/12=/104-19/60-x
5/12=85/60-x
5/12=17/12-x
5=12(17/12-x)
5=17-12x
12x=17-5
12x=12
x=1...............