Question
Solve the inequality
x∈(0,9)∪(9,36)
Evaluate
x2−36xx2−81<0
Find the domain
More Steps

Evaluate
x2−36x=0
Add the same value to both sides
x2−36x+324=324
Evaluate
(x−18)2=324
Take the root of both sides of the equation and remember to use both positive and negative roots
x−18=±324
Simplify the expression
More Steps

Evaluate
324
Write the number in exponential form with the base of 18
182
Reduce the index of the radical and exponent with 2
18
x−18=±18
Separate the inequality into 2 possible cases
{x−18=18x−18=−18
Calculate
More Steps

Evaluate
x−18=18
Move the constant to the right side
x=18+18
Add the numbers
x=36
{x=36x−18=−18
Cancel equal terms on both sides of the expression
{x=36x=0
Find the intersection
x∈(−∞,0)∪(0,36)∪(36,+∞)
x2−36xx2−81<0,x∈(−∞,0)∪(0,36)∪(36,+∞)
Separate the inequality into 2 possible cases
{x2−81>0x2−36x<0{x2−81<0x2−36x>0
Solve the inequality
More Steps

Evaluate
x2−81>0
Since the left-hand side is always positive or 0,and the right-hand side is always 0,the statement is true for any value of x,except when x2−81=0
x2−81=0
Rewrite the expression
x2−81=0
Move the constant to the right-hand side and change its sign
x2=0+81
Removing 0 doesn't change the value,so remove it from the expression
x2=81
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±81
Simplify the expression
More Steps

Evaluate
81
Write the number in exponential form with the base of 9
92
Reduce the index of the radical and exponent with 2
9
x=±9
Separate the equation into 2 possible cases
x=9x=−9
Exclude the impossible values of x
x∈(−∞,−9)∪(−9,9)∪(9,+∞)
{x∈(−∞,−9)∪(−9,9)∪(9,+∞)x2−36x<0{x2−81<0x2−36x>0
Solve the inequality
More Steps

Evaluate
x2−36x<0
Add the same value to both sides
x2−36x+324<324
Evaluate
(x−18)2<324
Take the 2-th root on both sides of the inequality
(x−18)2<324
Calculate
∣x−18∣<18
Separate the inequality into 2 possible cases
{x−18<18x−18>−18
Calculate
More Steps

Evaluate
x−18<18
Move the constant to the right side
x<18+18
Add the numbers
x<36
{x<36x−18>−18
Cancel equal terms on both sides of the expression
{x<36x>0
Find the intersection
0<x<36
{x∈(−∞,−9)∪(−9,9)∪(9,+∞)0<x<36{x2−81<0x2−36x>0
Since the left-hand side is always positive or 0,and the right-hand side is always 0,the statement is false for any value of x
{x∈(−∞,−9)∪(−9,9)∪(9,+∞)0<x<36{x∈/Rx2−36x>0
Solve the inequality
More Steps

Evaluate
x2−36x>0
Add the same value to both sides
x2−36x+324>324
Evaluate
(x−18)2>324
Take the 2-th root on both sides of the inequality
(x−18)2>324
Calculate
∣x−18∣>18
Separate the inequality into 2 possible cases
x−18>18x−18<−18
Calculate
More Steps

Evaluate
x−18>18
Move the constant to the right side
x>18+18
Add the numbers
x>36
x>36x−18<−18
Cancel equal terms on both sides of the expression
x>36x<0
Find the union
x∈(−∞,0)∪(36,+∞)
{x∈(−∞,−9)∪(−9,9)∪(9,+∞)0<x<36{x∈/Rx∈(−∞,0)∪(36,+∞)
Find the intersection
x∈(0,9)∪(9,36){x∈/Rx∈(−∞,0)∪(36,+∞)
Find the intersection
x∈(0,9)∪(9,36)x∈/R
Find the union
x∈(0,9)∪(9,36)
Check if the solution is in the defined range
x∈(0,9)∪(9,36),x∈(−∞,0)∪(0,36)∪(36,+∞)
Solution
x∈(0,9)∪(9,36)
Show Solution
