Answer all the questions plsss

Asked by rishubest29 | 11th Jun, 2020, 01:19: AM

Expert Answer:

10. If a = 9 - 4 sqrt{5}, find the value of [a -1/a]2
Solution: 
1 over a equals fraction numerator 1 over denominator 9 minus 4 square root of 5 end fraction cross times fraction numerator 9 plus 4 square root of 5 over denominator 9 plus 4 square root of 5 end fraction equals fraction numerator 9 plus 4 square root of 5 over denominator 81 minus 80 end fraction equals 9 plus 4 square root of 5
open parentheses a minus 1 over a close parentheses squared equals open parentheses 9 minus 4 square root of 5 minus 9 minus 4 square root of 5 close parentheses squared equals open parentheses negative 8 square root of 5 close parentheses squared equals 320
 
 
 
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Answered 10th question because it is fully visible.

Answered by Renu Varma | 11th Jun, 2020, 07:50: PM