allerySolve: x^2 = 9. The solutions are
Ax equals 9 and minus 9 by direct read
Bx = 3 and only positive root applies
Cx = -3 and only negative root applies
Dx = 3 or x = -3
Answer & Solution
Correct answer: D. x = 3 or x = -3
1. Rewrite x^2 = 9 as x^2 - 9 = 0.
2. Factor using difference of squares: (x - 3)(x + 3) = 0.
3. Either x = 3 or x = -3.
4. Both roots are valid, so option A.
_Source: Selina Concise Mathematics Class 10, Ch 5 Quadratic Equations (Mistral OCR'd PDF), section on simple quadratics_
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