Inlocuim in prima expresie, toti termenii, astfel:
a+(a+18)+2a+(a+b)/2=132 => a+(a+18)+2a+(a+a+18)/2=132
Desfacem parantezele: a+a+18+2a+(2a+18)/2=132 => 2a+18+2a+(2a+18)/2=132
=> 4a+18+(2a+18)/2=132 => aducem la acelasi numitor =>
8a+36+2a+18=132x2 => 10a=264-54 => 10a=210 => a=210/10 => a=21