Question

Solve by completing the square.


`x^(2) -8x-5=-3`

Type in the step before you square both sides.

format ex.
`(x+2)^(2) =-87`

Answer 1

x^2 -8x -5 = -3

x^2 -8x -2 = 0

We complete the square by:

1) Moving the "non X" term to the right:

x^2 -8x = 2

2) Dividing the equation by the coefficient of X²

The coefficient of x is 1 so we don't do anything

3) Now here's the "completing the square" stage in which we:

• take the coefficient of X

that is -8

• divide it by 2

-8 ÷ 2 = -4

• square that number

-4*-4 = 16

• then add it to both sides of the equation.

x^2 -8x +16 = 2 +16

That becomes

(x -4)^2 = 18

we take the square root of both sides:

(x -4) = sqr root (18)

x1 = sqr root (18) +4

AND

(x+4) = sqr root (18) -4

x1 = sqr root (18) +4 = 4.2426406871 + 4 = 8.2426406871

x2 = sqr root (18) -4 = = 4.2426406871 - 4 = .2426406871

Explanation: