1) Daca a+b=25 si b+c=35.....calculati 3a+6b+3c...?
2)Determinati multimea: A=2x∈N...3x+12/21. este subunitara ..
Am nevoie repede ...ajutor va rog !!!
1)a+b=25<=>3a+3b=75 b+c=35<=>3b+3c=105 le aduni membru cu membru =>3a+6b+3c=180 2)(3x+12)/21 subunitara =>3x+12<21<=>3x<9<=>x<3 x∈N =>x∈{0,1,2} A={2x\x∈N}<=>A={0,2,4}