\((x-3)[(x-3)^2-(x^2+3x+9)]+9(x+1)^2=15\)

\((x-3)[(x^2-6x+9)-(x^2+3x+9)]+9x^2+18x+9=15\)

\(-(x-3)9x+9x(x+2)=6\)

\(=>9x(-x+3+x+2)=6\)

\(=>45x=6\)

\(=>x=\dfrac{6}{45}\)

anh đề là \(\sqrt{x+3}\) mà có phải \(\sqrt{x}+3\)đâu

=\(\dfrac{\left(x-4\right)-5-\sqrt{x+3}}{\left(\sqrt{x+3}\right)\left(\sqrt{x}-2\right)}=\dfrac{x-9-\sqrt{x+3}}{\left(\sqrt{x+3}\right)\left(\sqrt{x}-2\right)}\)

=\(\dfrac{\sqrt{x-3}\sqrt{x+3}-\sqrt{x+3}}{\left(\sqrt{x+3}\right)\left(\sqrt{x}-2\right)}=\dfrac{\left(\sqrt{x-3}+1\right)\sqrt{x+3}}{\left(\sqrt{x+3}\right)\left(\sqrt{x}-2\right)}\)

=\(\dfrac{\sqrt{x-3}+1}{\sqrt{x}-2}\)

câu này anh làm sai rồi

giải phương trình \(3\sqrt{x^2+5}-\sqrt{x^2+2x-4}=11-2x\)

=2+\(\sqrt{5}\)