First, add #color(red)(2.7)# to each side of the equation to isolate the #z# term while keeping the equation balanced:
#-1.2 + color(red)(2.7) = z/4.6 - 2.7 + color(red)(2.7)#
#1.5 = z/4.6 - 0#
#1.5 = z/4.6#
Now, multiply each side of the equation by #color(red)(4.6)# to solve for #z# while keeping the equation balanced:
#color(red)(4.6) xx 1.5 = color(red)(4.6) xx z/4.6#
#6.9 = cancel(color(red)(4.6)) xx z/color(red)(cancel(color(black)(4.6)))#
#6.9 = z#
#z = 6.9#
To check the solution we need to substitute #6.9# for #z# in the original problem and calculate the right side of the equation to ensure it equals #-1.2#
#-1.2 = 6.9/4.6 - 2.7#
#-1.2 = 1.5 - 2.7#
#-1.2 = -1.2#
Because both sides of the equation equal #-1.2# we have verified the solution we obtained is correct.