Teacher's Guide - Pearson

Extension Activity 18.2 (Student’s Book page 328)1. a) x 5 22 or 21b) x 5 23c) No real roots2. 2, 1 and 03. b 2 2 4ac 5 0 è one root(turns on the x-axis)b 2 − 4ac < 0 è no roots(turns before x-axis)b 2 − 4ac > 0 è two roots(cuts x-axis at two points)4. Can be 2 (maximum), 1 or zero (minimum).Exercise 18.2 (Student’s Book page 329)1. Solutions: (23;26); (22;26)2. Solutions: (22;4); (1;1)3. Solutions: (20.83;4); (4.83;4) (the quadratic formula is needed for this)4. Solutions: (4;16); (24;16)5. Solutions: (4;12); (23;12)Activity 18.4 (Student’s Book page 331)y2.521.510.50x0.5 1 1.5Let the equation be y 5 k(x 2 0)(x 2 1).The TP is at ( 1__ ​;2), so substitute this into the equation:2∴ 2 2 k( 1 2 2 0)(1 2 2 1)5 k( 1 2 )(21 2 )5 2 1 4 k∴ k 5 28The correct equation is y = 28x(x 2 1)Chapter 18: Quadratic graphs111