Question

Calculati 5a+7b+cdaca 4a+7b=840 si a+c=120
Ajutatima va rog

Answer 1

$4a+7b=840 \\ a+c=120 \\ 5a+7b+c=? \\ 5a+7b+c=4a+7b+a+c=840+120=960 \\ \boxed{5a+7b+c=960}$