đkxđ: ....
\(\sqrt{x+4}+\sqrt{x+11}=x+27-x^2\)
\(\Leftrightarrow x+4+2\sqrt{\left(x+4\right)\left(x+11\right)}+x+1=x^2+729+x^4+54x-2x^3-54x^2\)
\(\Leftrightarrow2x+5+2\sqrt{\left(x+4\right)\left(x+11\right)}=x^4-2x^3-53x^2+54x+729\)
\(\Leftrightarrow2\sqrt{x^2+15x+44}=x^4-2x^3-53x^2+52x+724\)
\(\Leftrightarrow2\sqrt{x^2+15x+44}=\left(x-2\right)\left(x^3-53x-54\right)+616\)
.........