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


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