If AM and GM of the roots of a quadratic equation are 10 and 8 respectively then obtain the quadratic equation.
If AM and GM of the roots of a quadratic equation are 10 and 8 respectively then obtain the quadratic equation.

Answer : To find: The quadratic equation. Given: (i) AM of roots of quadratic equation is 10

(ii) GM of roots of quadratic equation is 8

Formula used: (i) Arithmetic mean between

(ii) Geometric mean between

Let the roots be p and q

Arithmetic mean of roots p and q            = 10

⇒           = 10

⇒ p + q = 20 = sum of roots … (i)

Geometric mean of roots p and q =        = 8

⇒ pq = 64 = product of roots … (ii)

Quadratic equation = x2 – (sum of roots)x + (product of roots) From equation (i) and (ii)

Quadratic equation = x2 – (20)x + (64)

= x2 –20x + 64 x2 –20x + 64