Examples
x-2x+4≥0x−2x+4≥0
Step 1
Find all the values where the expression switches from negative to positive by setting each factor equal to 00 and solving.
x-2=0x−2=0
x+4=0x+4=0
Step 2
Add 22 to both sides of the equation.
x=2x=2
Step 3
Subtract 44 from both sides of the equation.
x=-4x=−4
Step 4
Solve for each factor to find the values where the absolute value expression goes from negative to positive.
x=2x=2
x=-4x=−4
Step 5
Consolidate the solutions.
x=2,-4x=2,−4
Step 6
Step 6.1
Set the denominator in x-2x+4x−2x+4 equal to 00 to find where the expression is undefined.
x+4=0x+4=0
Step 6.2
Subtract 44 from both sides of the equation.
x=-4x=−4
Step 6.3
The domain is all values of xx that make the expression defined.
(-∞,-4)∪(-4,∞)(−∞,−4)∪(−4,∞)
(-∞,-4)∪(-4,∞)(−∞,−4)∪(−4,∞)
Step 7
Use each root to create test intervals.
x<-4x<−4
-4<x<2−4<x<2
x>2x>2
Step 8
Step 8.1
Test a value on the interval x<-4x<−4 to see if it makes the inequality true.
Step 8.1.1
Choose a value on the interval x<-4x<−4 and see if this value makes the original inequality true.
x=-6x=−6
Step 8.1.2
Replace xx with -6−6 in the original inequality.
(-6)-2(-6)+4≥0(−6)−2(−6)+4≥0
Step 8.1.3
The left side 44 is greater than the right side 00, which means that the given statement is always true.
True
True
Step 8.2
Test a value on the interval -4<x<2−4<x<2 to see if it makes the inequality true.
Step 8.2.1
Choose a value on the interval -4<x<2−4<x<2 and see if this value makes the original inequality true.
x=0x=0
Step 8.2.2
Replace xx with 00 in the original inequality.
(0)-2(0)+4≥0(0)−2(0)+4≥0
Step 8.2.3
The left side -0.5 is less than the right side 0, which means that the given statement is false.
False
False
Step 8.3
Test a value on the interval x>2 to see if it makes the inequality true.
Step 8.3.1
Choose a value on the interval x>2 and see if this value makes the original inequality true.
x=4
Step 8.3.2
Replace x with 4 in the original inequality.
(4)-2(4)+4≥0
Step 8.3.3
The left side 0.25 is greater than the right side 0, which means that the given statement is always true.
True
True
Step 8.4
Compare the intervals to determine which ones satisfy the original inequality.
x<-4 True
-4<x<2 False
x>2 True
x<-4 True
-4<x<2 False
x>2 True
Step 9
The solution consists of all of the true intervals.
x<-4 or x≥2
Step 10
The result can be shown in multiple forms.
Inequality Form:
x<-4orx≥2
Interval Notation:
(-∞,-4)∪[2,∞)
Step 11