Question

The roots of the equation 9x2 – bx + 81 = 0 will be equal, if the value of b is

Answer 1

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Answer 2

Answer: The value of b is 54

Step-by-step explanation:

Given: The roots of the equation $9x^2 -bx +81 = 0$ are equal

To find: The value of b

As we know

$D= b^2 - 4ac\\\\D= b^2 - 4\times 9\times 81 \\\\ \text {For equal roots the value of D is zero } \\\\ b^2 -4\times 9 \times 81 = 0\\\\b^2 = 4\times 9 \times 81 \\\\b= \sqrt{4\times 9\times 81 } \\\\b = 2\times 3\times 9 \\\\b= 54$

Hence, the value of b is 54