Question

The sum of the real roots of the equation $${x^2} + \left| x \right| - 6 = 0$$    is

A. $$4$$
B. $$0$$  
C. $$- 1$$
D. none of these
Answer :   $$0$$
Solution :
$$\eqalign{ & {\text{The given quadric equation is }}{x^2} + \left| x \right| - 6 = 0 \cr & {\text{Here, }}a = 1,{\text{ }}b = \pm 1{\text{ and }}c = - 6 \cr & {\text{As we know that }}D = {b^2} - 4ac \cr & {\text{Putting the value of }}a = 1,{\text{ }}b = \pm 1{\text{ and }}c = - 6 \cr & = {\left( { \pm 1} \right)^2} - 4 \times 1 \times - 6 \cr & = 1 + 24 \cr & = 25 \cr & {\text{Since, }}D \geqslant 0 \cr & {\text{Therefore, root of the given equation are real and distinct}}{\text{. }} \cr & {\text{Thus, sum of the roots be}} = 0. \cr} $$

Releted MCQ Question on
Algebra >> Quadratic Equation

Releted Question 1

If $$\ell ,m,n$$  are real, $$\ell \ne m,$$  then the roots by the equation: $$\left( {\ell - m} \right){x^2} - 5\left( {\ell + m} \right)x - 2\left( {\ell - m} \right) = 0$$         are

A. Real and equal
B. Complex
C. Real and unequal
D. None of these
Releted Question 2

The equation $$x + 2y + 2z = 1{\text{ and }}2x + 4y + 4z = 9{\text{ have}}$$

A. Only one solution
B. Only two solutions
C. Infinite number of solutions
D. None of these
Releted Question 3

Let $$a > 0, b > 0$$    and $$c > 0$$ . Then the roots of the equation $$a{x^2} + bx + c = 0$$

A. are real and negative
B. have negative real parts
C. both (A) and (B)
D. none of these
Releted Question 4

Both the roots of the equation $$\left( {x - b} \right)\left( {x - c} \right) + \left( {x - a} \right)\left( {x - c} \right) + \left( {x - a} \right)\left( {x - b} \right) = 0$$           are always

A. positive
B. real
C. negative
D. none of these.

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Quadratic Equation


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