Question

va rog frumos sa ma ajutati am doua probleme dificile dau 15 puncte caruia a facuto corect Calculati 5a+7b+c daca 4a+7b=840 si a+c=120 iar a doua  calculati 2a+9b+3c daca a+3b=120 si b+c = 40

 

Answer 1

a) 5a+7b+c=(4a+7b)+(a+c)=840+120=960
b) 2a+9b+3c=2a+6b+3b+3c=2*(a+3b)+3*(b+c)=2*120+3*40=240+120=360