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#
