Explicație pas cu pas:
ultima cifră:
[tex]({5}^{1}) = 5 \\ ({5}^{2}) = 5[/tex]
→
[tex]({5}^{20}) = ( {5}^{1}) = 5[/tex]
ultima cifră:
[tex]({7}^{1}) = 7 \\ ({7}^{2}) = 9 \\ ({7}^{3}) = 3 \\ ({7}^{4}) = 1 \\ ( {7}^{5}) = 7 [/tex]
→
[tex]{7}^{8} = {7}^{4 \times 2} = > ({7}^{8}) = ( {7}^{4}) = 1[/tex]
ultima cifră:
[tex]( {8}^{1}) = 8 \\ ( {8}^{2}) = 4 \\( {8}^{3}) = 2 \\( {8}^{4}) = 6 \\( {8}^{5}) = 8 [/tex]
→
[tex]{8}^{24} = {8}^{4 \times 6} = > ({8}^{24}) = ({8}^{4}) = 6[/tex]
=>
[tex]( {5}^{20} - {7}^{8} + {8}^{24} ) = ( {5}^{20} + {8}^{24} - {7}^{8}) \\ = (5 + 6 - 1) = (11 - 1) = (10) = 0[/tex]
