The first step to solving this equation is to do the necessary mathematics to isolate the #d# terms on one side of the equation and the constants on the other side of the equation while keeping the equation balanced:

#color(red)(16d) - 16d + 4 = color(red)(16d) + d#

#(color(red)(16d) - 16d) + 4 = color(red)(16d) + d#

#0 + 4 = 16d + d#

#4 = 16d + d#

Next, we can combine like terms:

Hint: remember (#color(green)(k = 1k)#)

#4 = (16 + 1)d#

#4 = 17d#

Now, we can solve for #d# while keeping the equation balanced:

#4/color(red)(17) = (17d)/color(red)(17)#

#4/17 = (color(red)(cancel(color(black)(17)))d)/color(red)(cancel(color(black)(17)))#

#4/17 = d# or #d = 4/17#