Question
Mathematics Question on Quadratic Equations
If α, β are the roots of the equation
x2−(5+3log35−5log53)+3(3(log35)31−5(log53)32−1)=0
then the equation, whose roots are α + 1/β and β + 1/α , is
A
3x2 – 20x – 12 = 0
B
3x2 – 10x – 4 = 0
C
3x2 – 10x + 2 = 0
D
3x2 – 20x + 16 = 0
Answer
3x2 – 10x – 4 = 0
Explanation
Solution
The correct answer is (B) : 3x2 – 10x – 4 = 0
3log35−5log53=3log35−(3log35)log53=0
3(log35)31−5(log53)32=5(log53)32−5(log53)32=0
Note: In the given equation ‘ x ’ is missing.
So α, β are the roots of x2 – 5x + 3(-1) = 0
α+β+α1+β1=(α+β)+αβα+β
=5−35
=310
(α+β1)(β+α1)=2+αβ+αβ1
=2−3−31=3−4
So Equation must be option (B).