[tex] {2}^{n + 3} + {2}^{n + 1} + {2}^{n} = 88. \\ {2}^{n} \times {2}^{3} + {2}^{n} \times {2}^{1} + {2}^{n} = 88. \\ {2}^{n}({2}^{3} + 2 + 1) = 88. \\ {2}^{n} \times 11 = 88. \\ {2}^{n} = 88 \div 11. \\ {2}^{n} = 8. \\ {2}^{n} = {2}^{3}. \\ = > n = 3.[/tex]
