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Help with homework lesson for review to study for test.

Help with homework lesson for review to study for test.-example-1
User Ammerzon
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We have the expression:


(y^2-9)/(y^2+y-12)

The restricted values of y are those values that make the denominator 0. This is the same as solving the equation:


y^2+y-12=0

This term can be factorized as:


\begin{gathered} y^2+y-12=(y+4)(y-3) \\ \Rightarrow(y+4)(y-3)=0 \end{gathered}

This is true for y = -4 and y = 3. So the restricted values for y are:


y\\e\mleft\lbrace-4,3\mright\rbrace

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