How do you solve x2>4 using a sign chart?

1 Answer
Dec 16, 2016

The answer is x],2[]2,+[

Explanation:

Let f(x)=x24

Let's rewrite the equation as

x24=(x+2)(x2)>0

Now we can do the sign chart

aaaaxaaaaaaaa2aaaa2aaaa+

aaaax+2aaaaaaaaa+aaaa+

aaaax2aaaaaaaaaaaaa+

aaaaf(x)aaaaaa+aaaaaaaa+

Therefore,

f(x)>0 when x],2[]2,+[