Question

How do you solve `x^{2} - 8= 0`?

Answer 1

`x=+-2sqrt2`

Explanation:

`"isolate "x^2" by adding 8 to both sides"`

`x^2=8`

`color(blue)"take the square root of both sides"`

`sqrt(x^2)=+-sqrt8larrcolor(blue)"note plus or minus"`

`rArrx=+-2sqrt2`

Answer 2

`x= +-2sqrt(2)`

Explanation:

`x^{2} - 8= 0`

first add 8 to both sides:

`x^{2}= 8`

now take the square root of both sides, remember you must use `+-` the square root on the right side:

`sqrt(x^{2})= +-sqrt(8)`

`x= +-2sqrt(2)`

Answer 3

`x=+-2sqrt2`

Explanation:

`color(blue)(x^2-8=0`

To, solve this, we need to isolate `x^2` in one side of the equation. To do that, we can add or subtract the same number in both sides of the equation.

Add `8` both sides

`rarrx^2-8+color(red)(8)=0+color(red)(8)`

`rarrx^2=8`

Now, take the square root of both sides,

`rarrsqrt(x^cancel2)=+-sqrt8`

`rarrx=+-sqrt8`

Now, take the prime factors of `8`

`rarrx=+-sqrt(underbrace(2*2)*2)`

`color(green)(rArrx=+-2sqrt2`

Remember that `+-` means plus or minus