a x 42 + 720 - 80 = 1060 => a x 42 +640 = 1060 | scadem 640 din stanga si dreapta egalitatii => a x 42 +640 - 640 = 1060 - 640 => a x 42= 420 => a=420:42 = 10
100 - b:16 +350:7 = 144 => 100 - b:16+50=144 => b:16=150 - 144 => b:16=6
=> b = 6 x 16 =96
E=100 x 10 - 10 x 96 = 1000-960=40
