In the following expression, what values are not allowable as substitutions for the variable $x$x? Write your answer as an equation. If there is more than one value, make sure to enter all appropriate values separated by a comma.
$\frac{1}{x}$1x
In the following expression, what values are not allowable as substitutions for the variable $x$x? Write your answer as an equation. If there is more than one value, make sure to enter all appropriate values separated by a comma.
$\frac{4}{15x}$415x
In the following expression, what values are not allowable as substitutions for the variable $z$z? Write your answer as an equation. If there is more than one value, make sure to enter all appropriate values separated by a comma.
$\frac{1}{z+7}$1z+7
In the following expression, what values are not allowable as substitutions for the variable $y$y? Write your answer as an equation. If there is more than one value, make sure to enter all appropriate values separated by a comma.
$\frac{y}{y-8}$yy−8