Question

Solve the equation :x^2-4x-8=0

Answer 1

Answer:

x^2 - 4x=8

x^2 - 4x+4=12

(x-2)^2 =12

x-2=+-v(12)

x=2+-2v3

Answer 2

Solution of the equation is $2 + 2\sqrt{3}$ and $2 - 2\sqrt{3}$ .

• To solve the equation we need to find the roots of the equation.
• Given equation is : $x^{2}$ - 4x - 8 = 0.
• Solving the above given quadratic equation , we find the roots.

• (By using the standard formula)
• Comparing the equation with $ax^{2}$  + bx + c = 0 , we get

a = 1, b= -4 and c= -8

x = $\frac{-b + \sqrt{b^{2}-4ac } }{2a}$ and x = $\frac{-b - \sqrt{b^{2}-4ac } }{2a}$

x = $\frac{4 + \sqrt{4^{2}-4(1)(-8) } }{2}$ and x = $\frac{4 - \sqrt{4^{2}-4(1)(-8) } }{2}$

x = $\frac{4 + \sqrt{48} }{2}$ and x = $\frac{4 - \sqrt{48} }{2}$

x = $\frac{4 + 4\sqrt{3} }{2}$ and x = $\frac{4 - 4\sqrt{3} }{2}$

x = $2 + 2\sqrt{3}$ and x = $2 - 2\sqrt{3}$