Question

3x²+7x–20=0,Find the roots of the given equation by the method of perfect square.

Answer 1

Solution :

Given Quadratic equation 3x²+7x-20=0

=> 3x² + 7x = 20

Divide each term by 3 , we get

=> x² + (7/3)x = 20/3

=> x² + 2*x*(7/6) = 20/3

=> x² + 2*x*(7/6)+(7/6)² = 20/3 +(7/6)²

=> ( x + 7/6 )² = 20/3 + 49/36

=> ( x + 7/6 )² = ( 240 + 49 )/36

=> ( x + 7/6 )² = 289/36

=> x + 7/6 = ± √(289/36)

=> x = -7/6 ± 17/6

=> x = (-7+17)/6 Or x = ( -7-17)/6

=> x = 10/6 or x = -24/6

=> x = 5/3 or x = -4

Therefore ,

5/3 , -4 are two roots of given

quadratic equation.

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