Given,
25190−19190−8190+2190
Now \left({25}^{190} - {19}^{190}\right), {8}^{190}, {2}^{190}aredivisibleby2,as{25}^{190}willgiveremainderas1and{19}^{190}willgiveremainderas1whendividedby2,socombined{25}^{190} - {19}^{190}willgiveremainder0</p><p>Now,(25190−8190) and \left(- {19}^{190} + {2}^{190}\right)aredivisibleby17,{a}^{n} - {b}^{n}isdivisiblebya - bifniseven,<br/>Sogivennumberisdivisibleby34asitisdivisibleby2 \text{ and } 17both,</p><p>Now,{25}^{190} = {\left(7 \times 3 + 4\right)}^{190},dividingby7weget,</p><p>{\left(7 \times 3 + 4\right)}^{190} = {4}^{190} = {16}^{95} = {2}^{95} = 4 \cdot {8}^{31}</p><p>Nowwhen4 \cdot {\left(7 + 1\right)}^{31}dividedby7willgiveremainderas4 \cdot 1 = 4</p><p>And{19}^{190} = {\left(7 \times 3 - 2\right)}^{190},whendividedby7weget,</p><p>{\left(7 \times 3 - 2\right)}^{190} = {\left(- 2\right)}^{190} = {2}^{190} = 2 \times {8}^{63} = 2 \times {\left(7 + 1\right)}^{63}</p><p>So,when2 \times {\left(7 + 1\right)}^{63}dividedby7willgiveremainderas2</p><p>Similarly{8}^{190} = {\left(7 + 1\right)}^{190}willgive1remainder</p><p>And{2}^{190} = 2{\left(7 + 1\right)}^{63}willgive1remainder,</p><p>Socombiningallweget,{25}^{190} - {19}^{190} - {8}^{190} + {2}^{190} = 4 - 2 - 1 + 1 = 5<br/>⇒Notdivisibleby7,soitwillnotbedivisibleby14