Subtract the right side from both sides, leaving zero on the right side.
[(x-1)/(x+2)] - [x/(x-2)] >= 0
Get common denominator.
Multiply first term by (x-2)/(x-2).
Multiply second term by (x+2)/(x+2).
[(x-2)(x-1)]/[(x-2)(x+2)] - [(x+2)x]/[(x+2)(x-2)] >= 0
Multiply.
(x^2 - x - 2x + 2)/(x^2 - 4) - (x^2 + 2x)/(x^2 - 4) >= 0
Combine the terms into one rational expression:
(x^2 - 3x + 2 - x^2 - 2x)/(x^2 - 4) >= 0
Simplify:
(-5x + 2)/(x^2 - 4) >= 0
Find the value of x that will satisfy the equality part of the inequality.
Determine what value of x will make this true:
(-5x + 2)/(x^2 - 4) = 0
To do this, determine what value of x will make numerator equal to zero:
-5x + 2 = 0
-5x + 2 - 2 = 0 - 2
-5x = -2
x = 2/5
Thus, when x=2/5, the rational expression on the right side will be equal to zero.
x = 2/5 is a solution
Determine which value(s) of x will make the rational expression undefined.
To do this, determine what value of x will make denominator equal to zero:
x^2 - 4 = 0
x^2 = 4
x = 2, x = -2
Thus, when x = 2 or x = -2, the rational expression on the right side will be undefined.
x = 2 and x = -2 are not solutions
So far, we know that
x = -2 is not a solution
x = 2/5 is a solution
x = 2 is not a solution.
We need to choose four values for x to represent all the possible values of x to determine all the valid solutions.
Choose an x value less than -2
Choose an x value between -2 and 2/5
Choose an x value between 2/5 and 2
Choose an x value greater than 2
Choose an x value less than -2: x = -3
Substitute this into the inequality:
(-5x + 2)/(x^2 - 4) >= 0
(-5(-3) + 2)/((-3)^2 - 4) >= 0
(15 + 2)/(9 - 4) >= 0
17/5 >= 0 is true
So x values less than -2 are solutions.
Choose an x value between -2 and 2/5: x = -1
Substitute this into the inequality:
(-5x + 2)/(x^2 - 4) >= 0
(-5(-1) + 2)/((-1)^2 - 4) >= 0
(5 + 2)/(1 -4) >= 0
7/-3 >= 0 or -7/3 >= 0 is not true
So x values beteen -2 and 2/5 are not solutions.
Choose an x value between 2/5 and 2: x = 1
Substitute this into the inequality:
(-5x + 2)/(x^2 - 4) >= 0
(-5(1) + 2)/((1)^2 - 4) >= 0
(-5 + 2)/(1 - 4) >= 0
-3/-3 >= 0 or 1 >= 0 is true
So x values between 2/5 and 2 are solutions.
Choose an x value greater than 2: x = 3
Substitute this into the inequality:
(-5x + 2)/(x^2 - 4) >= 0
(-5(3) + 2)/((3)^2 - 4) >= 0
(-15 + 2)/(9 - 4) >= 0
-13/5 >= 0 is not true.
So x values greater than 2 are not solutions.
So we now know that:
x values less than -2 are solutions
x = -2 is not a solution
x values beteen -2 and 2/5 are not solutions
x = 2/5 is a solution
x values between 2/5 and 2 are solutions
x = 2 is not a solution
x values greater than 2 are not solutions
Therefore the solutions for this inequality are represented as:
-infinity < x < -2 and 2/5 <= x < 2
(-infinity, -2) and [2/5, 2)
How would I solve: x-1/x+2 is greater than or equal to x/x-2
2 answers
Note: small correction to my previous answer...
Both occurrences of "rational expression on the right side" should be replaced with just "rational expression".
Both occurrences of "rational expression on the right side" should be replaced with just "rational expression".