Question

Aflati valoarea lui ,,a'': 13-4x3:[2x11-1x5-(10x2-5xa)]+2x3=13

Answer 1

13-12:[22-5-(20-5xa)]+6=13
19-12:(17-20+5xa)=13
12:(5xa-3)=6
5xa-3=6/12      (6/12=1/2)
5xa=1/2+3       (1/2+3=1/2+6/2=7/2)
5xa=7/2
a=7/2/5             (7/2/5=7/2*1/5=7/10)
a=7/10