Question
Solve the inequality
Solve the inequality by testing the values in the interval
Solve the inequality by separating into cases
Solve for x
−4≤x≤4
Alternative Form
x∈[−4,4]
Evaluate
x2≤16
Move the expression to the left side
x2−16≤0
Rewrite the expression
x2−16=0
Move the constant to the right-hand side and change its sign
x2=0+16
Removing 0 doesn't change the value,so remove it from the expression
x2=16
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±16
Simplify the expression
More Steps

Evaluate
16
Write the number in exponential form with the base of 4
42
Reduce the index of the radical and exponent with 2
4
x=±4
Separate the equation into 2 possible cases
x=4x=−4
Determine the test intervals using the critical values
x<−4−4<x<4x>4
Choose a value form each interval
x1=−5x2=0x3=5
To determine if x<−4 is the solution to the inequality,test if the chosen value x=−5 satisfies the initial inequality
More Steps

Evaluate
(−5)2≤16
Calculate
52≤16
Calculate
25≤16
Check the inequality
false
x<−4 is not a solutionx2=0x3=5
To determine if −4<x<4 is the solution to the inequality,test if the chosen value x=0 satisfies the initial inequality
More Steps

Evaluate
02≤16
Calculate
0≤16
Check the inequality
true
x<−4 is not a solution−4<x<4 is the solutionx3=5
To determine if x>4 is the solution to the inequality,test if the chosen value x=5 satisfies the initial inequality
More Steps

Evaluate
52≤16
Calculate
25≤16
Check the inequality
false
x<−4 is not a solution−4<x<4 is the solutionx>4 is not a solution
The original inequality is a nonstrict inequality,so include the critical value in the solution
−4≤x≤4 is the solution
Solution
−4≤x≤4
Alternative Form
x∈[−4,4]
Show Solution