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Quadratic Formula

What is it?

To find the x-intercepts/zeroes in an equation that cannot be factored, you can use the quadratic formula

 

 

In order to use this formula, your equation needs to be in standard form - y=ax^2 +bx + c

Substitute the a, b, and c values into the formula to get your answer.

Example 1

3x^2 - 14x - 5                    a = 3, b = -14, c = -5

 

x = 14     -14^2 - 4(3)(-5)

                     2(3)

 

  = 14      256

                  6

 

The exact roots are 14+ 256     and 14 - 256             

                                         6                       6

The approximate roots are 16.67 and 11.33

 

In the case of a negative number inside the square root, the solution is not possible because you cannot square root a negative number.

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