If 1 is a root of the quadratic equation and the quadratic equation has equal roots, find the value of b.

For a quadratic equation, ax2 + bx + c = 0,


D = b2 – 4ac


If D = 0, roots are equal


Given, 1 is a root of the quadratic equation


3 + a – 2 = 0


a = -1


Now, the quadratic equation has equal roots


x2 + 6x + b = 0 has equal roots


D = 36 – 4b = 0


b = 9


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