Find the values of y for which the expression \(\frac{y^2 - 9y + 18}{y^2 + 4y - 21}\) is undefined
Answer Details
The given expression will be undefined when its denominator is equal to zero since division by zero is undefined. So we need to find the values of y that make the denominator zero.
\begin{align*}
y^2 + 4y - 21 &= 0\\
(y+7)(y-3) &= 0
\end{align*}
The denominator is equal to zero when either y+7=0 or y-3=0. Therefore, the expression is undefined when y=-7 or y=3.
So, the answer is (c) 3, -7.