The number of real roots of the equation x   ∣ x − 2 ∣ + 3 ∣ x − 3 ∣ + 1 = 0 is:

Question:

The number of real roots of the equation

xx2+3x3+1=0 is:

📷 Question Image:

The number of real roots of the equation  x   ∣ x − 2 ∣ + 3 ∣ x − 3 ∣ + 1 = 0 is:


Short Solution (Text):

Critical points for the absolute values are x=2x=2 and x=3x=3. Solve piecewise in the three intervals.

1) Region x<2x<2:
x2=2x,  x3=3x|x-2|=2-x,\; |x-3|=3-x. The equation becomes

x(2x)+3(3x)+1=0x2x+10=0x2+x10=0.x(2-x) + 3(3-x) + 1 = 0 \\ \Rightarrow -x^2 - x + 10 = 0 \\ \Rightarrow x^2 + x - 10 = 0.

Discriminant Δ=1+40=41\Delta = 1 + 40 = 41. Roots:

x=1±412.x = \frac{-1 \pm \sqrt{41}}{2}.

Numeric values: 1+4122.7016\dfrac{-1+\sqrt{41}}{2}\approx 2.7016 and 14123.7016\dfrac{-1-\sqrt{41}}{2}\approx -3.7016.
Only x3.7016x\approx -3.7016 lies in this region (x<2x<2) → one valid root here.

2) Region 2x<32 \le x < 3:
x2=x2,  x3=3x|x-2|=x-2,\; |x-3|=3-x. The equation becomes

x(x2)+3(3x)+1=0x25x+10=0.x(x-2) + 3(3-x) + 1 = 0 \\ \Rightarrow x^2 - 5x + 10 = 0.

Discriminant Δ=2540=15<0\Delta = 25 - 40 = -15 <0no real roots in this interval.

3) Region x3x\ge 3:
x2=x2,  x3=x3|x-2|=x-2,\; |x-3|=x-3. The equation becomes

x(x2)+3(x3)+1=0x2+x8=0.x(x-2) + 3(x-3) + 1 = 0 \\ \Rightarrow x^2 + x - 8 = 0.

Discriminant Δ=1+32=33\Delta = 1 + 32 = 33. Roots:

x=1±3322.3723,  3.3723.x = \frac{-1 \pm \sqrt{33}}{2}\approx 2.3723,\; -3.3723.

Neither root satisfies x3x\ge 3no valid roots here.


Final Answer:
Number of real roots = 1
(the only real solution is x=14123.7016x = \dfrac{-1-\sqrt{41}}{2}\approx -3.7016).

Comments

Popular posts from this blog

Balanced Redox Reaction: Mg + HNO₃ → Mg(NO₃)₂ + N₂O + H₂O | JEE Chemistry

Speed Reduced by 20%, Reaches 16 Minutes Late – Find Actual Time | Motion in Straight Line – JEE Question

⚡ Balance the Redox Equation: Zn + NO₃⁻ → Zn²⁺ + NH₄⁺ in Basic Medium | JEE Mains Redox Reaction