x^4>9x^2

Solution

x^{4} > 9 x^{2}

x < - 3 or x > 3

Interval Notation

(- \infty, - 3) \cup (3, \infty)

Solution steps

x^{4} > 9 x^{2}

Rewrite in standard form

x^{4} - 9 x^{2} > 0

Factor

x^{4} - 9 x^{2} : x^{2} (x + 3) (x - 3)

x^{2} (x + 3) (x - 3) > 0

Identify the intervals

x < - 3 or x > 3

(4 r x t - 8 r^{2} x + x^{2}) (- 6 r x^{2} + 5 r x t - 2 x^{2})

\frac{- j ( - k ) ^{- 2}}{j ^{2} k}

\frac{\frac{1}{4} ( \frac{1}{4} - 1 ) ( \frac{1}{4} - 2 )}{3 !}

s^{4} + 12 s^{3} + 64 s^{2} + 128 s

\frac{( 2 e ^{(- x^{2} - 4 y^{2})} y - 8 e ^{(- x^{2} - 4 y^{2})} y ( 4 x ^{2} + y ^{2} ) )}{2 e ^{(- x^{2} - 4 y^{2})} y}