Question

Let $$\alpha \ne \beta $$  and $${\alpha ^2} + 3 = 5\alpha $$   while $${\beta ^2} = 5\beta - 3.$$   The quadratic equation whose roots are $$\frac{\alpha }{\beta }$$ and $$\frac{\beta }{\alpha }$$ is

A. $$3{x^2} - 31x + 3 = 0$$
B. $$3{x^2} - 19x + 3 = 0$$  
C. $$3{x^2} + 19x + 3 = 0$$
D. None of these
Answer :   $$3{x^2} - 19x + 3 = 0$$
Solution :
Clearly $$\alpha ,\beta $$  are the roots of the equation $${x^2} - 5x + 3 = 0.$$    Use $$\alpha + \beta = 5,\alpha \beta = 3.$$

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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