(50×y+160)-60=500 быстрее
(50y+160)-60=500; 50y+160=560; 50y=400; y=8.
(50×y+160)-60=500 (50у+160) = 500 + 60 50у+160 = 560 50y = 560 - 160 50y = 400 y = 8