Home » Aptitude » Quadratic Equation » Question
  1. Find the quadratic equation whose roots are reciprocal of the roots of the equation 3x2 - 20x +17 = 0
    1. 17x2 - 20x + 3 = 0
    2. 17x2 + 20x + 3 = 0
    3. 17x2 - 20x - 3 = 0
    4. None of these
Correct Option: A

The given quadratic equation is
3x2 - 20x +17 = 0 .......(1)
Compare with ax2 + bx + c = 0, we get
a = 3, b = −20, c = 17
The roots of (1) are given by

x =
- b ± √b2 - 4ac
=
20 ± √400 - 4(3)(17)
2a
2 × 3
x =
20 ± √196
=
20 + 14
,
20 - 14
6
6
6
x =
34
,
6
=
17
, 1
6
6
3
Hence the roots of (1) are
17
and 1.
3
So we have to form an equation whose are
3
and 1
17

Sum of the roots =
3
+ 1 =
20
17
17
Product of the roots =
3
x 1 =
3
17
17
Hence, the required equation is
x2 -
20
x +
3
= 0
17
17

⇒ 17x2 - 20x + 3 = 0.



Your comments will be displayed only after manual approval.