Question 620191
Let the variable be a
You are told
{{{a = K (bc^2)/d}}}
now plug in the values of  a= -14, b=5, c=8, and d=20 
and solve for K
{{{-14 = K (5*8^2)/20}}}
{{{-14 = K (64/4)}}}
{{{-14/16 = K}}}
Plug in K
{{{a = (-14/16)*(bc^2)/d}}}
now plug in b=4, c=6, and d=9 and solve for a
{{{a =(-14/16)*(4*6^2)/9}}}