First, add #z# to both sides of the equation (shown in blue). Then, subtract #2# from both sides (shown in green).
# 14-z=2 #
# 14-zcolor(blue)+color(blue)z=2color(blue)+color(blue)z #
# 14color(red)cancelcolor(black)(-zcolor(blue)+color(blue)z)=2color(blue)+color(blue)z #
# 14+0=2color(blue)+color(blue)z #
# 14=2+z #
# 14color(green)-color(green)2=2+zcolor(green)-color(green)2 #
# 14color(green)-color(green)2=2color(green)-color(green)2+z #
# 14color(green)-color(green)2=color(red)cancelcolor(black)(2color(green)-color(green)2)+z #
# 14color(green)-color(green)2=0+z #
# 14color(green)-color(green)2=z #
# 12=z #
That's the solution. Hope this helped!