Răspuns: ( am pus a pt a evita confuzia)
2+10×[7×15-2 ×a-16]×5-3=222
2+10x(7x15 - 2xa- 16) x5 = 222+3= 225
10x(7x15 - 2xa- 16)x5=225-2=223
10x(7x15 - 2xa- 16)x5=223
10x(105 -2xa-16)x5= 223
10x(89 -2xa)x5=223
(890 - 20xa)x5= 223
4450 - 100xa= 223
4450-223= 100xa
4227= 100xa => a= 4227:100= 42,27