Given:#" "2d-5=7#
Determine the value of #d#
Add #color(magenta)(5)# to both sides. This turns the 5 on the left of the = into 0
#color(green)(2d-5=7" "->" "2d-5color(magenta)(+5)=7color(magenta)(+5))#
But #-5+5 = 0# giving:
#" "->" "color(green)(2d+0=12)#
Divide both sides by #color(magenta)(2)#. This turns the 2 in #2d# into 1
#" "color(green)( ->" "2/(color(magenta)(2)) xx d=12/(color(magenta)(2))#
But #2/2=1# giving
#" "color(green)(->" "1xxd=6)#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#d=6#
