[tex]Domain:\\\\x+3\geq0\ \wedge\ 2x-1\geq0\\\\x\geq-3\ \wedge\ x\geq0.5\\\\D:x\in[0.5;\ \infty)[/tex]
[tex]\sqrt{x+3}-\sqrt{2x-1}=-2\qquad\text{square of both sides}\\\\(\sqrt{x+3}-\sqrt{2x-1})^2=(-2)^2\qquad\text{use}\ (a-b)^2=a^2-2ab+b^2\\\\(\sqrt{x+3})^2-2(\sqrt{x+3})(\sqrt{2x-1})+(\sqrt{2x-1})^2=4\qquad\text{use}\ (\sqrt{a})^2=a\\\\x+3-2\sqrt{(x+3)(2x-1)}+2x-1=4\qquad\text{combine like terms}\\\\3x+2-2\sqrt{(x+3)(2x-1)}=4\qquad\text{subtract 3x + 2 from both sides}\\\\-2\sqrt{(x+3)(2x-1)}=2-3x\qquad\text{square of both sides}\\\\\left(-2\sqrt{(x+3)(2x-1)}\right)^2=(2-3x)^2[/tex]
[tex]4(x+3)(2x-1)=2^2-2(2)(3x)+(3x)^2\qquad\text{use distributive property}\\\\(4x+12)(2x-1)=4-12x+9x^2\\\\(4x)(2x)+(4x)(-1)+(12)(2x)+(12)(-1)=4-12x+9x^2\\\\8x^2-4x+24x-12=4-12x+9x^2\\\\8x^2+20x-12=4-12x+9x^2\qquad\text{subtract }\ 9x^2\ \text{from both sides}\\\\-x^2+20x-12=4-12x\qquad\text{add 12 and}\ 12x\ \text{from both sides}\\\\-x^2+36x=16\qquad\text{change the signs}\\\\x^2-36x=-16\\\\x^2-2(x)(16)=-16\qquad\text{add}\ 16^2\ \text{to both sides}[/tex]
[tex]\underbrace{x^2-2(x)(16)+16^2}_{(a-b)^2=a^2-2ab+b^2}=16^2-16\\\\(x-16)^2=256-16\\\\(x-16)^2=240\iff x-16=\pm\sqrt{240}\\\\x-16=\pm\sqrt{16\cdot15}\\\\x-16=-\sqrt{16}\cdot\sqrt{15}\ \vee\ x-16=\sqrt{16}\cdot\sqrt{15}\\\\x-16=-4\sqrt{15}\ \vee\ x-16=4\sqrt{15}\qquad\text{add 16 to both sides}\\\\x=16-4\sqrt{15}\notin D\ \vee\ x=16+4\sqrt{15}\\\\\boxed{x=4(4+\sqrt{15})}[/tex]
