Răspuns:
[tex] {7}^{27} - 2 \times {7}^{26} + 14 \times {7}^{25} = \\ 7 {}^{27} - 2 \times 7^{26} + 2 \times 7 \times {7}^{25} = \\ {7}^{27} - 2 \times {7}^{26} + 2 \times {7}^{26} = \\ (7 - 2 + 2) \times {7}^{26} = \\ = 7 \times {7}^{26 } = {7}^{27} [/tex]
