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ANSWER:

2 \leqslant x < 2 \sqrt{ \frac{7}{<klux>3</klux>} }

Step-by-step explanation:

\sqrt{x + 3}  >  \sqrt{x - 1}  +  \sqrt{x - 2}

Expression inside square root must be NON negative, so

x+3 ≥ 0, x-1 ≥ 0 and x-2 ≥ 0

⇒ x ≥ -3, x ≥ 1 and x ≥ 2

x ≥ 2

Squaring both side of inequality, we get

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

6 - x  >  2 \sqrt{x - 1}  \sqrt{x - 2}  \geqslant 0

So 6-x ≥ 0

x ≤ 6

Squaring the EQUATION again, we get

36  - 12x +  {x}^{2}   >  4(x - 1)(x - 2)

36 - 12x +  {x}^{2}   >  4( {x}^{2}  - 3x + 2)

36 - 12x +  {x}^{2}   >  4 {x}^{2}  - 12x + 8

3 {x}^{2}  - (36 - 8) < 0

{x}^{2}   -   \frac{28}{3}  < 0

(x + \sqrt{ \frac{28}{3} })( x  -  \sqrt{ \frac{28}{3} })  < 0

- 2 \sqrt{ \frac{7}{3} }  < x < 2 \sqrt{ \frac{7}{3} }

x must also satisfy the inequalities

2  \leqslant x \leqslant 6

Hence

2 \leqslant x < 2 \sqrt{ \frac{7}{3} }



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