Răspuns: 10 -> numarul
Explicație pas cu pas:
Notez numarul cu ,,a"
[ (3 × a + 12 ) × 5 - 2 ] : 8 = 26
(3 × a + 12 ) × 5 - 2 = 26 × 8
(3 × a + 12 ) × 5 - 2 = 208
(3 × a + 12 ) × 5 = 208 + 2
(3 × a + 12 ) × 5 = 210
3 × a + 12 = 210 : 5
3 × a + 12 = 42
3 × a = 42 - 12
3 × a = 30
a = 30 : 3
a = 10 → numarul, aflat prin metoda mersului invers
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Verific:
[ ( 3 × 10 + 12 ) × 5 - 2 ] : 8 = (42 × 5 - 2) : 8 = (210 - 2) : 8 = 208 : 8 = 26
