264:[16+(42:a-15:3):2=11

Răspuns :

Buna!

264:[16+(42:a-15:3)]:2=11

264:[16+(42:a-5)]:2=11

264:[16+(42/a-5)]x1/2=11

132:(16+42/a-5)=11

132:(11+42/a)=11

132:11a+42/a=11

132xa/11a+42=11

132a/11s+42=11

132a=11(11a+42)

132a+121a+462

132a-121a=462

11a=462

a=42

SPER CA TE AM AJUTAT!