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What is the excluded value of x for x^2+3x+2/x^2+2x+1

User Jillan
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2 Answers

5 votes
factoring we get

(x + 2)(x + 1) / (x + 1)(x + 1)

The excluded value is x = -1
User Gaf King
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2 votes

Answer: The required value of x is
x=-1.

Step-by-step explanation: We are given to find the excluded value for the following rational expression:


E=(x^2+3x+2)/(x^2+2x+1).

First, we need to factorize both numerator and denominator and then we should check the values of x for which the expression becomes undefined.

We have


E\\\\=(x^2+3x+2)/(x^2+2x+1)\\\\\\=(x^2+2x+x+2)/(x^2+x+x+1)\\\\\\=(x(x+2)+1(x+2))/(x(x+1)+1(x+1))\\\\\\=((x+2)(x+1))/((x+1)(x+1)).

Now, we can cancel
(x+1) by
(x+1), only if
x\\eq 1,
because

if
x=-1, then
x+1=0
and we cannot divide 0 by 0.

Therefore, if
x\\eq 1, then


E=((x+2)(x+1))/((x+1)(x+1))=(x+2)/(x+1),

which is again well-defined because
x\\eq -1 and so the denominator never become zero.

Thus, the excluded value of x is
x=-1.

User Miguel Salas
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