Solve x^2-9 = 0
Solve ax² + bx + c = 0 using the quadratic formula with discriminant analysis.
x2-9=0
Solve by isolating x² and taking the square root of both sides:
Move the constant to the other side by adding 9:
x2 = 9
Since x² = k has two solutions, x = +√k and x = −√k:
x = ±√9
x = ±3
x = ±3
How to solve x^2-9 = 0
To solve x^2-9 = 0, we can try factoring, use the quadratic formula, or complete the square. The solution is x = ±3.
This is a second-degree quadratic equation — the highest power of the variable is 2. Quadratic equations can have two real roots, one repeated root, or two complex roots.
Frequently asked questions
What is the answer to x^2-9 = 0?
The answer is x = ±3.
What method is used?
factoring when possible, or the quadratic formula x = (−b ± √(b²−4ac)) / 2a. The discriminant b²−4ac determines the number and type of solutions.
How do I verify this?
Substituting the solution(s) back into x^2-9 = 0 confirms both sides are equal.