Question:medium

If A.M. and G.M. of roots of a quadratic equation are 8 and 5, respectively, then obtain the quadratic equation.

Updated On: Jan 21, 2026
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Solution and Explanation

Let the roots of the required quadratic equation be α and β.

It is given that the A.M. of the roots is 8.

\[ \text{A.M.} = \frac{\alpha + \beta}{2} = 8 \]

∴ \( \alpha + \beta = 16 \) … (1)

It is also given that the G.M. of the roots is 5.

\[ \text{G.M.} = \sqrt{\alpha \beta} = 5 \]

Squaring both sides, we get

∴ \( \alpha \beta = 25 \) … (2)

The quadratic equation whose roots are α and β is given by:

\[ x^2 - (\alpha + \beta)x + \alpha \beta = 0 \]

Substituting the values from (1) and (2):

\[ x^2 - 16x + 25 = 0 \]

Thus, the required quadratic equation is

\[ x^2 - 16x + 25 = 0 \]

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