Quadratic Formula Math Example 4

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Example 4

easy
Solve x2−9=0x^2 - 9 = 0.

Solution

  1. 1
    Factor as a difference of squares: (x−3)(x+3)=0(x - 3)(x + 3) = 0.
  2. 2
    Solutions: x=3x = 3 or x=−3x = -3.

Answer

x=3 or x=−3x = 3 \text{ or } x = -3
Recognize x2−9x^2 - 9 as a difference of squares: a2−b2=(a−b)(a+b)a^2 - b^2 = (a-b)(a+b).

About Quadratic Formula

A formula giving the exact solutions to any quadratic equation ax2+bx+c=0ax^2 + bx + c = 0 directly from its three coefficients.

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More Quadratic Formula Examples

Example 1 easy

Solve [formula] by factoring.

Example 2 medium

Solve [formula] using the quadratic formula.

Example 3 hard

Solve [formula] using the quadratic formula.

Example 5 hard

Solve [formula] and describe the solutions.

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