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Use the quadratic formula when factoring is not possible to solve quadratic equations. The discriminant determines the number and type of solutions. Examples and questions included.
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Sec 5.6 Quadratic Formula & Discriminant
Quadratic Formula(Yes, it’s the one with the song!) If ax2 + bx + c = 0 and a ≠ 0, then the solutions (roots) are: Use the quadratic formula when you can’t factor to solve a quadratic equation The solutions are the x-intercepts (zeros) of the parabola
Examples • x2 + 5x – 14 = 0 a=1, b=5, c=-14 OR
What are your QUESTIONS?
Discriminant: b2 – 4ac • The discriminant tells you how many solutions and what type you will have If positive: 2 real solutions If negative: 2 imaginary solutions If zero: 1 real solution
Find the discriminant and give the number and type of solutions. 9x2 + 6x + 1 = 0 a=9, b=6, c=1 b2 – 4ac = (6)2 – 4(9)(1) =36 – 36 = 0 1 real solution x2 – 6x + 10 = 0 c. x2 – 6x + 8 = 0 Examples