 # 4.8 Do Now: practice of 4.7 The area of a rectangle is 50. If the width is x and the length is x + 10. Solve for x by completing the square.

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4.8 Do Now: practice of 4.7 The area of a rectangle is 50. If the width is x and the length is x + 10. Solve for x by completing the square.

Algebra II 4.8: Quadratic Formula HW: p.296 (16, 20, 32, 34) Test 4.5, 4.7, 4.8, word problems: Wednesday, Nov. 5 th

Quadratic Formula  The quadratic formula is used to solve any quadratic equation.  Quadratic Formula: If ax 2 + bx + c = 0, then

Discriminant  The discriminant = b 2 – 4ac  The value of the discriminant tells you how many solutions the quadratic equation has. 0  1 real solution. 0  1 real solution. positive number  2 real solutions. positive number  2 real solutions. negative number  2 imaginary solutions. negative number  2 imaginary solutions.

Find the discriminant and determine the number of solutions. 1.) x 2 – 8x + 16 = 0 2.) 5x 2 + 20x = -21

Use the Quadratic Formula to find the solutions to the equation. 1.) x 2 – 4x – 5 = 0

Use the Quadratic Formula to find the solutions to the equation. 2.) 3 – 8v – 5v 2 = 2v

4.8: Use the Quadratic Formula to find the solutions to the equation. 3.) 4x 2 + 3 = x 2 – 7x

4.8: Use the Quadratic Formula to find the solutions to the equation. 4.) 4x 2 + 3x – 12 = 3 – 3x

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