x^2 – x – 20   find the positive discriminant

X^2 – 16x + 64  find zero discriminant

3x2 + 4x + 2   find negative discriminant





1) Value for :   a=1, b= -1, c = 

2)Calculation

3)Value of discriminant 

4)What the value of the discriminant means to the graph



explain what this means to the graph : y=ax^2 + bx + c





A. x^2 – x – 20   find the positive discriminant

 1. Values for : a = 1, b = -1 and c = -20

 2. To find the discriminant x = b^2 - 4ac

                               = (-1)^2 - 4(1)(-20)

                               = 1 + 80

 3.                            = 80        -------------> positive discriminant

 4. Discriminant determines the solution of the equation and x intercept.

    since we have positive discriminant, we have 2 solutions and 2 x-intercept.







B. x^2 – 16x + 64  find zero discriminant

 1. Values for : a = 1, b = -16, c = 64

 2. Solve for the discriminant x = b^2 - 4ac

                                 = (-16)^2 - 4(1)(64)

                                 = 256 - 256

 3.                              = 0 -------------> Zero Discriminant

 4. Since we have Zero discriminant, we have 1 soution and 1 x-intercept







C. 3x^2 + 4x + 2   find negative discriminant

 1. Value for: a = 3, b = 4, c = 2

 2. x = b^2 - 4ac

      = 4^2 - 4(3)(2)

      = 16 - 24

 3.   = -8 --------------> negative discriminant

 4. Since it is a negative discriminant, there is no solution or no x-intercept



Example Let us solve for x: x^2 – x – 20

                            (x -5)(x + 4)

                            x = 5  and x = -4 2 solutions





                           x^2 – 16x + 64

                           (x -8)(x - 8)

                            x = 8   one solution



You can solve for x for 3x^2 + 4x + 2 using quadratic formula and you will get no solution.



I hope this help

 

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