1.

(7+√5)+(7-√5)=?

Answer» 14
{tex}\\begin{array}{l}\\left(7+\\sqrt5\\right)\\left(7-\\sqrt5\\right)\\\\By\\;identity\\;:\\;(a+b)(a-b)=\\;a^{2\\;}-b^2\\\\=\\;7^{2\\;}-\\;(\\sqrt5)^2\\\\=\\;49\\;-\\;5\\\\=\\;44\\;\\end{array}{/tex}
44
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