Home
Class 12
MATHS
If the equations x^(3) - mx^2 - 4 = 0 a...

If the equations `x^(3) - mx^2 - 4 = 0 and x^(3) + mx + 2 = 0 .m in R` have one common root, then find the values of m.

Text Solution

AI Generated Solution

The correct Answer is:
To find the values of \( m \) such that the equations \( x^3 - mx^2 - 4 = 0 \) and \( x^3 + mx + 2 = 0 \) have one common root, we can follow these steps: ### Step 1: Let the common root be \( r \). Assume that \( r \) is the common root of both equations. ### Step 2: Substitute \( r \) into both equations. From the first equation: \[ r^3 - mr^2 - 4 = 0 \quad \text{(1)} \] From the second equation: \[ r^3 + mr + 2 = 0 \quad \text{(2)} \] ### Step 3: Set the two equations equal. Since both equations equal \( r^3 \), we can set them equal to each other: \[ mr^2 + 4 = -mr - 2 \] ### Step 4: Rearranging the equation. Rearranging gives: \[ mr^2 + mr + 4 + 2 = 0 \] \[ mr^2 + mr + 6 = 0 \quad \text{(3)} \] ### Step 5: Factor the quadratic equation. Equation (3) is a quadratic in \( m \): \[ m(r^2 + r) + 6 = 0 \] From this, we can express \( m \): \[ m = -\frac{6}{r^2 + r} \quad \text{(4)} \] ### Step 6: Find the values of \( m \) for specific roots. To find specific values of \( m \), we can test for rational roots of the original equations. Let's try \( r = 1 \) and \( r = -2 \). #### Case 1: \( r = 1 \) Substituting \( r = 1 \) into equation (4): \[ m = -\frac{6}{1^2 + 1} = -\frac{6}{2} = -3 \] #### Case 2: \( r = -2 \) Substituting \( r = -2 \) into equation (4): \[ m = -\frac{6}{(-2)^2 + (-2)} = -\frac{6}{4 - 2} = -\frac{6}{2} = -3 \] ### Conclusion Both cases yield the same value for \( m \): \[ \boxed{-3} \]

To find the values of \( m \) such that the equations \( x^3 - mx^2 - 4 = 0 \) and \( x^3 + mx + 2 = 0 \) have one common root, we can follow these steps: ### Step 1: Let the common root be \( r \). Assume that \( r \) is the common root of both equations. ### Step 2: Substitute \( r \) into both equations. From the first equation: \[ ...
Promotional Banner

Topper's Solved these Questions

  • THEORY OF EQUATIONS

    CENGAGE|Exercise Exercise 2.11|8 Videos
  • THEORY OF EQUATIONS

    CENGAGE|Exercise Exercise 2.12|11 Videos
  • THEORY OF EQUATIONS

    CENGAGE|Exercise Exercise 2.9|12 Videos
  • STRAIGHT LINES

    CENGAGE|Exercise JEE Advanced Previous Year|4 Videos
  • THREE DIMENSIONAL GEOMETRY

    CENGAGE|Exercise Question Bank|20 Videos

Similar Questions

Explore conceptually related problems

If the equations x^(2) + 2x -3=0 and x^(2) + 3x-m=0 have a common root, then the non- zero value of m.

Find the sum of all the values of m so that , the equations 3x^(2)-2mx-4=0" and x^(2)-4mx+2=0 " may have a common root.(" Can the equations have a common nonreal root)

For the two equations x^(2)+mx + 1 =0 and x^(2) + x + m = 0 , what is the value of m for which these equations have at least one common root?

If x^(2)+4ax+3=0 and 2x^(2)+3ax-9=0 have a common root,then the value of a,the common root are

Find the value of lamda so that the equations x^(2)-x-12=0 and lamdax^(2)+10x+3=0 may have one root in common. Also, find the common root.

If x=2 and x=3 are roots of the equation 3x^(2)-mx+2n=0 , then find the values of m and m.

If he roots of the equation12x^(2)-mx+5=0 are in the ratio 2:3 then find the value of m.

If the equation x^(2)-2mx+7m-12=0 has equal roots, then m=

Determine the values o m for which equations 3x^(2)+4mx+2=0 and 2x^(2)+3x-2=0 may have a common root.