Bonjour,
[tex]x^2 = 27\\ x^2-27 = 0\\ (x-\sqrt{27})(x+\sqrt{27} )= 0\\ \left(x-3\sqrt{3}\right)\left(x+3\sqrt 3\right) = 0\\ S = \left\{3\sqrt 3 ; -3\sqrt 3\right\} [/tex]
[tex]9 = (x-5)^2\\ 9-(x-5)^2 = 0\\ \left[3-(x-5)\right]\left[3+(x-5)\right] = 0\\ \left(8-x\right)\left(x-2\right) = 0\\ \left(x-8\right)\left(x-2\right) = 0\\ S = \left\{8 ; 2\right\}[/tex]
[tex]A = (2\sqrt{3} - 2 )+( \sqrt{27}+1)\\ A = 2\sqrt{3}-2 +3\sqrt{3}+1\\ A = 5\sqrt{3} -1[/tex]
