Solving quadratic .....?

Question

Hey guys i would like to ask if anyone have tips or exampls for this topic solving quadratic equation for example :

x square - 6x +4 =0
=(x square -6/2x)square -(6/2)square+4=0..
and so on...

+ i need tips for studying E.maths in singapore thank you if you really do give website or tips for me :) and also studying tips for other subject!!

Answer 1

ax^2 + bx + c = 0. b +/- square root(b^2 - 4ac) ALL divided by 2a. Verbally, it's B plus or minus the square root of B squared minus 4ac all over 2a.

for example:

2x^2 + 5x + 1.

-5 +/- square root of (5^2 - 4(2)(1)) all divided by 2(2)

= -5 +/- square root of (25-8) all divided by 4

= -5 + square root of 17 all over 4 and -5 - square root of 17 all over 4.

Answer 2

Since the coefficient of x² is 1 and the coefficient of x is even, completing the square is easy:

x² - 6x + 4 = 0
x² - 6x + 9 = -4 + 9
(x - 3)² = 5
x - 3 = ±√5
x = 3 ±√5

Answer 3

x² - 6x + 4 = 0

a = 1, b = -6, c = 4

x = -b ± √ b² - 4ac over 2a

= -(-6) ±√(-6)² - 4(1)(4) over 2(1)

= 6 ±√36-16 over 2

= 6 ±√20 over 2

6 + √20 over 2 = 5.236
or
6 - √20 over 2 = 0.764