How do you solve x^2-4x>=0 using a sign chart?

1 Answer
Oct 15, 2017

We first consider where x^2 - 4x = 0

i.e. when x(x - 4) = 0

Hence, x = 0 or x = 4

We then need to consider three seperate regions.

i.e. x < 0, 0 < x < 4 and x > 4

For x < 0, we have that x^2 - 4x > 0

For 0 < x < 4, we have that x^2 - 4x < 0

and for x > 4 we have that x^2 - 4x > 0

Hence, for x^2 - 4x >=0 we have two regions.

i.e. x <=0 or x >=4

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