a) 7*x-8=15 b) 1:2-1:5x=1:3=0,(3)
7*x=15+8=23 0,5-0,2*x=0,(3)
x=23:7=3,2857 5supra10-2supra10*x=3supra9
3supra10*x=3supra9
x=3supra9:3suprazece=>prima neschimbata si a doua inversata x=3supra9*10supra3 se simplifica prin diagonala 3 cu 3 si x=10supra9
c)x:2:5-1:3=2 x:2:5-0,(3)=2 x:2:5-3supra9=2supra1 x:2:5=2supra1 amplificam cu9+3supra9=21supra9 x:2=21supra9*5supra1=105supra9 x=105supra9*2supra1 x=210supra9