#1.# First, distribute the #2# into the #(-6x+9)# by first multiplying the #2# by #-6x# and then by #9# to get #-12x+18#
#-12x+18=-66#
#2.# Then, since #18# does not have an #x# with it, you can subtract 18 from both sides of the equation, taking away the #18# from the left side and subtracting #18# from #-66# as well.
This makes sure that both sides of the equals sign are equal. When you solve equations like this, always try to look for ways to get the #x# term alone on one side. So, by doing this step, you have
#-12x=-84#
#3.# Look for ways to isolate #x# again. This is an easy one since #x# is just multiplied by #-12#. Divide both sides by #-12# to get #x=7#.
#(-12x)/(-12) = (-84)/(-12)#
#x=7#
I hope this was helpful! :)