Afla nr necunoscut : a) 8 × 4 + a = 6 × 9 + 16 ÷ 2 b) a - 9 × 8 = 32 ÷ 4 + 225 c) (6×6 ÷ 4 ×b) - 25 ÷ 5 = 11 × 2​