Question

помогите пожалуйста 89 и 91 сделать

Answer 1

89
$( \sqrt{2} -3) \sqrt{5+6 \sqrt{( \sqrt{2} +1)^2} } =( \sqrt{2} -3) \sqrt{5+6( \sqrt{2} +1)} =$$( \sqrt{2} -3) \sqrt{5+6 \sqrt{2} +6} =( \sqrt{2} -3) \sqrt{11+6 \sqrt{2} } =$$( \sqrt{2} -3) \sqrt{(3+ \sqrt{2})^2 } =( \sqrt{2} -3)*(3+ \sqrt{2} =2-9=-7$
91
$\sqrt{(8- \sqrt{7} )^2} + \sqrt{( \sqrt{7}-2)^2 } =8- \sqrt{7} + \sqrt{7} -2=6$