Direction: What should come in place of the question mark (?) in the question? |
A) 6
B) \[6+2\sqrt{5}\]
C) \[6\sqrt{5}\]
D) \[6-2\sqrt{5}\]
E) None of these
Correct Answer: A
Solution :
\[{{(\sqrt{5}-1)}^{2}}=?-2\sqrt{5}\] \[\Rightarrow \,{{\left( \sqrt{5} \right)}^{2}}+{{(1)}^{2}}-2\times \sqrt{5}\times 1\] \[=?-2\sqrt{5}\] \[\Rightarrow \,\,5+1-2\sqrt{5}=?-2\sqrt{5}\] \[\Rightarrow \,\,6-2\sqrt{5}=?-2\sqrt{5}\] \[\therefore ?=6\]You need to login to perform this action.
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