3*(10+2*(40-2*(28-3*5)))-7x=51
3*(10+2*(40-2*(28-15)))-7x=51
3*(10+2*(40-2*13))-7x=51
3*(10+2*(40-26))-7x=51
3*(10+2*14)-7x=51
3*(10+28)-7x=51
3*38-7x=51
114-7x=51
7x=114-51
7x=63
x=63/7
x=9
a+(a+2)+(a+2+2)=15
3a+6=15
3a=15-6
3a=9
a=9/3
a=3-a rezolvat in prima zi
5-a rezolvat in a doua zi
7-a rezolvat in a treia zi
TE ROG poti sa imi multumesti si sa ma pui ca cea mai buna la acest raspuns , daca ti-a placut . iti multumesc si succes.