Key Numbers of Inequality...1

[nycmathguy]

Section 2.7
Question 12

x/(x + 2) - 2/(x - 1) < 0

LCD = (x + 2)(x - 1)

[x(x - 1) - 2(x + 2)]/LCD < 0

(x^2 - x -2x - 4)/LCD < 0

(x^2 - 3x - 4)/LCD < 0

(x - 4)(x + 1)/(x + 2)(x - 1) < 0

(x - 4)( x + 1) < 0

Replace less than sign with equal sign.

(x - 4)(x + 1) = 0

Set each factor to zero and solve for x.

x - 4 = 0

x = 4

x + 1 = 0

x = -1

The key numbers are x = 4 & x = -1.

You say?

 

[MathLover1]

correct

 

[nycmathguy]

correct

Not bad at all. I basically skimmed through the lesson due to lack of time and got it right.

 

[nycmathguy]

correct

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