## Presentation on theme: "Solving Quadratic Equations Quadratic Equations: Think of other examples?"— Presentation transcript:

Solving Quadratic Equations General Form: Can a = 0? Can b = 0? Can c = 0? Not Quadratic! Linear Quadratic!

Solving Quadratic Equations Null Law If then either a = 0 or b = 0 Solve ab So, either Therefore, 2 answers!!

Examples

Thinking question Remember to make one side ZERO first!

Thinking question

Solving Quadratic Equations To solve a quadratic equation, first put it in general form: ax 2 + bx + c = 0 Factorise the equation. Apply Null Law by letting each factor be equal to zero and solve for the variable.

Solving Quadratic Equations Example: Solve: x 2 – 5x + 3 = 17 Put in general form: x 2 – 5x – 14 = 0 Factor: (x + 2)(x – 7) = 0

Solving Quadratic Equations Solve: x 2 – 5x + 3 = 17 (x + 2)(x – 7) = 0 Set each factor equal to zero and solve: x + 2 = 0 x – 7 = 0 x = -2 x = 7 So the solutions to x 2 – 5x + 3 = 17 are x = -2 and x = 7

Thinking question

NO!!

Word Problems Find two consecutive positive odd numbers such that the sum of their squares is 74. Remember?