B. the answer is b!!!!!!!!!
The given equation, x9 - 5x3 + 6 = 0, is not a quadratic equation because the exponent of the first term is 9 while that of the second term is 3. The square of 3. If we are to square x3, we should only be getting x6 instead of x9. Therefore, the answer is NO.
The seventh number would have to be 11