Question

Solve the following quadratic equation using formula method only 

x² - 6x + 4 = 0

Answer 1

x² - 6x + 4 = 0

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

D = b² - 4ac 

= (-6)² - 4(1)(4)

= 36 - 16

= 20

x = ${\displaystyle \frac{-\text{b}\pm \sqrt{{\text{b}}^2-4\text{ac}}}{2a}}$

x = ${\displaystyle \frac{6\pm \sqrt{20}}{2}}$

x = ${\displaystyle \frac{6+2\sqrt{5}}{2}}$ , x = ${\displaystyle \frac{6-2\sqrt{5}}{2}}$

x = ${\displaystyle 3+\sqrt{5}}$  ,   x = ${\displaystyle 3-\sqrt{5}}$