Question
Solve the inequality
Solve the inequality by testing the values in the interval
Solve the inequality by separating into cases
Solve for x
−8≤x≤8
Alternative Form
x∈[−8,8]
Evaluate
x2−64≤0
Rewrite the expression
x2−64=0
Move the constant to the right-hand side and change its sign
x2=0+64
Removing 0 doesn't change the value,so remove it from the expression
x2=64
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±64
Simplify the expression
More Steps

Evaluate
64
Write the number in exponential form with the base of 8
82
Reduce the index of the radical and exponent with 2
8
x=±8
Separate the equation into 2 possible cases
x=8x=−8
Determine the test intervals using the critical values
x<−8−8<x<8x>8
Choose a value form each interval
x1=−9x2=0x3=9
To determine if x<−8 is the solution to the inequality,test if the chosen value x=−9 satisfies the initial inequality
More Steps

Evaluate
(−9)2−64≤0
Subtract the numbers
More Steps

Evaluate
(−9)2−64
Simplify
92−64
Evaluate the power
81−64
Subtract the numbers
17
17≤0
Check the inequality
false
x<−8 is not a solutionx2=0x3=9
To determine if −8<x<8 is the solution to the inequality,test if the chosen value x=0 satisfies the initial inequality
More Steps

Evaluate
02−64≤0
Simplify
More Steps

Evaluate
02−64
Calculate
0−64
Removing 0 doesn't change the value,so remove it from the expression
−64
−64≤0
Check the inequality
true
x<−8 is not a solution−8<x<8 is the solutionx3=9
To determine if x>8 is the solution to the inequality,test if the chosen value x=9 satisfies the initial inequality
More Steps

Evaluate
92−64≤0
Subtract the numbers
More Steps

Evaluate
92−64
Evaluate the power
81−64
Subtract the numbers
17
17≤0
Check the inequality
false
x<−8 is not a solution−8<x<8 is the solutionx>8 is not a solution
The original inequality is a nonstrict inequality,so include the critical value in the solution
−8≤x≤8 is the solution
Solution
−8≤x≤8
Alternative Form
x∈[−8,8]
Show Solution
