как решить уравнение 100(19+(15х-84):6=4

100 * (19 + (15 * х - 84)/6) = 4; 

19 + (15 * x - 84)/6 = 4/100; 

19 + (15 * x - 84)/6 = 1/25; 

25 * (19 + (15 * x - 84)/6) = 0; 

25 * 19 + 25/6 * (15 * x - 84) = 0; 

475 + 25 * 15/6 * x - 25/6 * 84 = 0; 

475 + 375/6 * x - 350 = 0; 

125 + 375/6 * x = 0; 

375/6 * x = -125; 

375 * x = 6 * (-125); 

375 * x = -750; 

x = -750/375; 

x = -2.