12+{2×[32+(a-24)×5]:4}×3=75
12+{2×[32+5a-120]:4}×3=75 -12
{2×[32+5a-120]:4}×3=63
(5a - 88])× 3=63 × 2
5a - 88 = 21 × 2
5a = 42 +88
5a = 130
a = 130 : 5
a = 26
verificare
12+{2×[32+(26-24)×5):4}×3=
12+{2×[(32+10)]:4}×3=
12+[2×(42:4}]×3=
12+[2×(21/2)]×3=
12 + 21 × 3 =
12 + 63 = 75
deci intr-adevar a = 26
