Solve the equations.

a) [[$ \displaystyle\frac {x} {4} = 3 $]]

Answer: [[$ x = $]]

b) [[$ \displaystyle\frac {y} {2} = -8 $]]

Answer: [[$ x = $]]

c) [[$ \displaystyle\frac {z} {9} = 3 $]]

Answer: [[$ x = $]]

d) [[$ -\displaystyle\frac {x} {8} = 4 $]]

Answer: [[$ x = $]]