Lesson 5 The x-Intercepts of a Quadratic Relation Factor. x 2 + 15x + 36 x 2 – 5x - 14 5x 2 + 30x - 135 Compare the Equation of a Quadratic Relation to Its Graph 1. a) Graph the quadratic relation y = x 2 + 10x + 16. What are the x-intercepts? a) Factor the expression on the right side of the equal sign. b) Compare the x-intercepts to the constant terms on the binomial factors of the factored form of the relation (in the brackets). What do you notice? c) Graph the factored relation in Y 2 . What do you notice? 2. Complete the table. Find the x-intercepts without graphing. Relation Factored Form x-Intercepts y = x 2 + 10x + 21 y = x 2 – 8x + 15 y = x 2 + 2x - 24 y = x 2 - 49 3. Graph each factored relation from Question 2. Use the graphs to find the x-intercepts. How do these x-intercepts compare to those you found in question 2? 4. Reflect. Given a quadratic Relation in the form y = x 2 + bx + c, how can you find the x- intercepts without graphing?
Intercept form of a quadratic relation is y = a(x – r)(x – s). In some other textbooks, you may see it written as y = a(x – s)(x – t).
- Fall '14
- Graph Theory, Equals sign, ASCII