Te salut, Alin Gabriel!
Răspuns: a = 18
Explicație pas cu pas:
208 : [112 - (100 - 3 × a ) × 4 : 23] = 2
112 - (100 - 3 × a ) × 4 : 23 = 208 : 2
112 - (100 - 3 × a ) × 4 : 23 = 104
(100 - 3 × a ) × 4 : 23 = 112 - 104
(100 - 3 × a ) × 4 : 23 = 8
(100 - 3 × a ) × 4 = 8 × 23
(100 - 3 × a ) × 4 = 184
100 - 3 × a = 184 : 4
100 - 3 × a = 46
3 × a = 100 - 46
3 × a = 54
a = 54 : 3
a = 18 → numărul, aflat prin metoda mersului invers
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Verific:
208 : [112 - (100 - 3 × 18) × 4 : 23] = 2
= 208 : [112 - (100 - 54) × 4 : 23] =
= 208 : ( 112 - 46 × 4 : 23) =
= 208 : ( 112 - 184 : 23 ) =
= 208 : ( 112 - 8) =
= 208 : 104 =
= 2
