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Which equation shows the quadratic formula used correctly to solve 7x² = 9 + x for x?

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Given equation, 7x²=9+x

 7x² - x - 9 = 0

Here, a = 7, b = -1, c = -9

Now, b² - 4ac

(-1)² – 4.7.(-9)

1+252

253

Therefore,

        - b  ±  √ b²-4ac
x = ———————
                      2a

       - (-1)  ±  √ 253
x = ——————--
                      2.7

       1  ±  √ 253
x = —————
               14
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