\large \large \sqrt{x+3+4\sqrt{x-1}}+\sqrt{x+8-6\sqrt{x-1}}=5 (đkxđ x\geq 1 )
<=> \large \large \sqrt{x-1+4+4\sqrt{x-1}}+\sqrt{x-1+9-6\sqrt{x-1}}=5
<=> \large \large \sqrt{x-1+4\sqrt{x-1}+2^2}+\sqrt{x-1-6\sqrt{x-1}+3^2}=5
<=>\large \large \sqrt{(\sqrt{x-1}+2)^2}+\sqrt{(\sqrt{x-1}-3)^2}=5...