Afla numerele necunoscute

12574-4352-x=2918

15,824+x+9,720=27,72

3,475+x-2,643=897

9,752-x+1,305=10,000

47,584+16,759-a=28,435

90,842-a=74,370+5,728

a-(53,870-92,146)=143,867


a+14,029-76,343)=230,495
am nevoie de ajutor urgent ​