mathematics questions1C

Q1
x (x -10) + 5 = 0
x² - 10x + 5 = 0
x = [10 ±£(10² - 4(5)] /6
x = [10 ±£80] /6
x = [10 ±4£5] /6
x = [5 ± 2£5] /3

Q2
(3x + 2)(3x - 2) + 3x = 0
9x² + 3x - 4 = 0
x = [-3 ± £(3² + 4(9)(4)) / [(2)(9)]
x = [-3 ± £153 ] /18
x = [-3 ± 3£17 ] /18
x = [-1 ±£17 ] /6

Q3
(x – 3)² = (2x + 1)(x - 2)
x² - 6x + 9 = 2x² - 3x – 2
x² + 3x – 11 = 0
x = [-3 ± £(3² + 44) ] /2
x = [-3 ± £53 ] /2

2007-09-13 08:55:34 補充：
[s020141621] 講得啱，Q1答案應該係：x (x -10) + 5 = 0x² - 10x + 5 = 0x = [10 ±£(10² - 4(5)] /2 .....{£ = square root 呀}x = [10 ±£80] /2x = [10 ±4£5] /2x = 5 ± 2£5

Q1

x (x -10) + 5 = 0

x² - 10x + 5 = 0

x = [10 ±£(10² - 4(5)] /6 <~~~唔係除2咩 做咩除6@@?

x = [10 ±£80] /6

x = [10 ±4£5] /6

x = [5 ± 2£5] /3

2007-09-13 20:26:49 補充：
Roger
下次小心d la~~唔好計錯=3=