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