Teacher's Guide - Pearson

Project (Student’s Book page 316)1. d 5 71.5 m2. 0.007v 2 1 0.015v 2 20 5 0∴ v 5 52.4 km/h 21 (for 20 metres, from formula)0.007v 2 1 0.0015v 2 10 5 0∴ v 5 36.7 km/h 21 (for 10 metres)0.007v 2 1 0.0015v 2 5 5 0∴ v 5 25.7 km/h 21 (for 5 metres)Revision Exercise (Student’s Book page 317)1. a) (x 2 7)(x 2 5) 5 0∴ x 5 7 or x 5 5b) (x 1 10)(x 2 3) 5 0∴ x 5 210 or x 5 3c) y 5 0 or y 5 6d) b 2 2 b 2 20 5 0(b 2 5)(b 1 4) 5 0∴ b 5 5 or b 5 24e) h 5 ±kf) x 2 1 7x 2 30 5 0∴ (x 1 10)(x 2 3) 5 0∴ x 5 210 or x 5 3g) a 5 16 or a 5 22h) x 5 25 or x 5 33. a)40 1 2xx20 1 2xxb) l 5 40 1 2xw 5 20 1 2xc) Area walkway5 (40 1 2x)(20 1 2x) 2 8005 120x 1 4x 2d) 4x 2 1 120x 5 544∴ x 2 1 30x 2 136 5 0∴ (x 2 4)(x 1 34) 5 0∴ x 5 4 m (the answer can’t be negative)106 EXPLORING MATHEMATICS FORM 3