Quadratic inequalities

An inequality which contain terms in x² will usually have two solutions. For example,

x² < 4 (x x x = x² and -x x -x = x²)

Therefore:

(x²) < 4 and (-x)² < 4 (√ both sides)

x < 2 and -x < 2 (-1 both sides to move the minus from the variable to the number)

x < 2 and x < -2 (combine the solutions)

-2 < x < 2

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