Dacă a+2b=5 si b+2c=90 atunci calculati 5a+13b+6c,unde a,b,c sunt numere naturale.


Efectuati
450+{[3×(3+41-450÷15)÷31+2525÷25]×2-9240÷132}÷3
39+5×{2+3×[2+4×*2353-84×28)]}-49
2×{20+3×[250-7××(399-17×23)]}+215-10
49-{23+4×[25-(24÷3-32÷4)-20]+3}​