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QJEEM19Ma463a: JEE Main 2019 Mathematics - Class 11 JEEM19Ma463a Solution: The sum of the solutions of the equation (x > 0) is equal to:

The sum of the solutions of the equation
∣x−2∣+x(x−4)+2=0\left| {\sqrt x - 2} \right| + \sqrt x \left( {\sqrt x - 4} \right) + 2 = 0
(x > 0) is equal to:

Multiple Choice Options

  • A 9
  • B 12
  • C 4
  • D 10

Step-by-Step Verified Solution

Case 1 : When x≥2\sqrt x \ge 2

then ∣x−2∣=x−2\left| {\sqrt x - 2} \right| = \sqrt x - 2

∴\therefore The given equation becomes,

(x−2)\left( {\sqrt x - 2} \right) + x(x−4)+2\sqrt x \left( {\sqrt x - 4} \right) + 2 = 0

⇒\Rightarrow (x−2)\left( {\sqrt x - 2} \right) + x−4xx - 4\sqrt x + 2 = 0

⇒\Rightarrow x−3xx - 3\sqrt x = 0

⇒\Rightarrow x(x−3)\sqrt x \left( {\sqrt x - 3} \right) = 0

∴\therefore x\sqrt x = 0 or 3

x\sqrt x = 0 is not possible as x≥2\sqrt x \ge 2 .

So, x\sqrt x = 3

or xx = 9

Case 2 : When \sqrt x < 2

then ∣x−2∣=\left| {\sqrt x - 2} \right| = −(x−2)- \left( {\sqrt x - 2} \right) = 2−x2 - \sqrt x

∴\therefore The given equation becomes,

(2−x)\left( {2 - \sqrt x } \right) + x(x−4)+2\sqrt x \left( {\sqrt x - 4} \right) + 2 = 0

⇒\Rightarrow 2−x{2 - \sqrt x } + x−4xx - 4\sqrt x + 2 = 0

⇒\Rightarrow x−5x+4x - 5\sqrt x + 4 = 0

⇒\Rightarrow x−4x−x+4x - 4\sqrt x - \sqrt x + 4 = 0

⇒\Rightarrow x(x−4)\sqrt x \left( {\sqrt x - 4} \right) −(x−4)-\left( {\sqrt x - 4} \right) = 0

⇒\Rightarrow (x−4)\left( {\sqrt x - 4} \right) (x−1)\left( {\sqrt x - 1} \right) = 0

∴\therefore x\sqrt x = 4 or 1

x\sqrt x = 4 is not possible as \sqrt x < 2 .

∴\therefore x\sqrt x = 1

or xx = 1

So, Sum of all solutions = 9 + 1 = 10

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