JEE 2023 — Mathematics PYQ
JEE | Mathematics | 2023The number of real roots of the equation x∣x∣−5∣x+2∣+6=0, is
Choose the correct answer:
- A.
5
- B.
6
- C.
4
- D.
3
(Correct Answer)
3
Explanation
Solution
Hame equation x∣x∣−5∣x+2∣+6=0 ke cases banane honge:
Case 1: x≥0
Equation: x2−5(x+2)+6=0⟹x2−5x−4=0
-
Roots: x=25±25+16=25±41
-
Kyunki x≥0, sirf x=25+41 sahi hai. (1 root)
Case 2: -2 \le x < 0
Equation: −x2−5(x+2)+6=0⟹−x2−5x−4=0⟹x2+5x+4=0
-
(x+4)(x+1)=0⟹x=−4,−1
-
Is range mein sirf x=−1 aata hai. (1 root)
Case 3: x < -2
Equation: −x2−5(−(x+2))+6=0⟹−x2+5x+16=0⟹x2−5x−16=0
-
Roots: x=25±25+64=25±89
-
x=25−89≈25−9.4≈−2.2 (Is range mein hai). (1 root)
Total Roots: 1+1+1=3
Sahi vikalp (4) hai.
Explanation
Solution
Hame equation x∣x∣−5∣x+2∣+6=0 ke cases banane honge:
Case 1: x≥0
Equation: x2−5(x+2)+6=0⟹x2−5x−4=0
-
Roots: x=25±25+16=25±41
-
Kyunki x≥0, sirf x=25+41 sahi hai. (1 root)
Case 2: -2 \le x < 0
Equation: −x2−5(x+2)+6=0⟹−x2−5x−4=0⟹x2+5x+4=0
-
(x+4)(x+1)=0⟹x=−4,−1
-
Is range mein sirf x=−1 aata hai. (1 root)
Case 3: x < -2
Equation: −x2−5(−(x+2))+6=0⟹−x2+5x+16=0⟹x2−5x−16=0
-
Roots: x=25±25+64=25±89
-
x=25−89≈25−9.4≈−2.2 (Is range mein hai). (1 root)
Total Roots: 1+1+1=3
Sahi vikalp (4) hai.

