Question

If using the method of completing the square to solve the quadratic equation x^2+20x-6=0x
2
+20x−6=0,

Answer 1

Answer:

100 will have to be added to both sides to complete the square

Step-by-step explanation:

Given:

x^2+20x+28=0

x² + 20x + 28 = 0

x² + 20x = -28

Using completing the square method of solving quadratic equation

Find the square of half of the coefficient of x

Coefficient of x = 20

Half of the coefficient of x = 20/2

= 10

Square of the half of the coefficient of x = 10²

= 100

Add the square of the half of the coefficient of x to both sides of the equation

x² + 20x = -28

x² + 20x + 100 = -28 + 100

(x + 10)² = 72

Answer 2

$x^2 +20x -6 =0\\\\\implies x^2 + 2 \cdot 10 \cdot x +10^2 -10^2 -6 =0\\\\\implies (x +10)^2 -106=0\\\\\implies (x +10)^2 =106\\\\\implies x +10 = \pm\sqrt{106}\\\\\implies x = -10 \pm \sqrt{106}$