Question
Solve the inequality
Solve the inequality by testing the values in the interval
Solve the inequality by separating into cases
x∈(−22,0)∪(22,+∞)
Evaluate
x3>2x
Multiply both sides of the inequality by 2
x3×2>2x×2
Multiply the terms
2x3>2x×2
Multiply the terms
2x3>x
Move the expression to the left side
2x3−x>0
Rewrite the expression
2x3−x=0
Factor the expression
x(2x2−1)=0
Separate the equation into 2 possible cases
x=02x2−1=0
Solve the equation
More Steps

Evaluate
2x2−1=0
Move the constant to the right-hand side and change its sign
2x2=0+1
Removing 0 doesn't change the value,so remove it from the expression
2x2=1
Divide both sides
22x2=21
Divide the numbers
x2=21
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±21
Simplify the expression
More Steps

Evaluate
21
To take a root of a fraction,take the root of the numerator and denominator separately
21
Simplify the radical expression
21
Multiply by the Conjugate
2×22
When a square root of an expression is multiplied by itself,the result is that expression
22
x=±22
Separate the equation into 2 possible cases
x=22x=−22
x=0x=22x=−22
Determine the test intervals using the critical values
x<−22−22<x<00<x<22x>22
Choose a value form each interval
x1=−2x2=−42x3=42x4=2
To determine if x<−22 is the solution to the inequality,test if the chosen value x=−2 satisfies the initial inequality
More Steps

Evaluate
2(−2)3>−2
Multiply the terms
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Evaluate
2(−2)3
Calculate the product
−(−2)4
A negative base raised to an even power equals a positive
−24
−24>−2
Calculate
−16>−2
Check the inequality
false
x<−22 is not a solutionx2=−42x3=42x4=2
To determine if −22<x<0 is the solution to the inequality,test if the chosen value x=−42 satisfies the initial inequality
More Steps

Evaluate
2(−42)3>−42
Multiply the terms
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Evaluate
2(−42)3
Evaluate the power
2(−322)
Multiply the numbers
−162
−162>−42
Calculate
−0.088388>−42
Calculate
−0.088388>−0.353553
Check the inequality
true
x<−22 is not a solution−22<x<0 is the solutionx3=42x4=2
To determine if 0<x<22 is the solution to the inequality,test if the chosen value x=42 satisfies the initial inequality
More Steps

Evaluate
2(42)3>42
Multiply the terms
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Evaluate
2(42)3
Evaluate the power
2×322
Multiply the numbers
162
162>42
Calculate
0.088388>42
Calculate
0.088388>0.353553
Check the inequality
false
x<−22 is not a solution−22<x<0 is the solution0<x<22 is not a solutionx4=2
To determine if x>22 is the solution to the inequality,test if the chosen value x=2 satisfies the initial inequality
More Steps

Evaluate
2×23>2
Calculate the product
24>2
Calculate
16>2
Check the inequality
true
x<−22 is not a solution−22<x<0 is the solution0<x<22 is not a solutionx>22 is the solution
Solution
x∈(−22,0)∪(22,+∞)
Show Solution
