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

3 Answers
Jim G.
May 23, 2018

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

Bill Jorgensen
May 23, 2018

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)

Veddesh phi
May 23, 2018

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

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