remember you can do anything to an equaiton as long as you do it to boh sides ad try to get unknown to one side 9n-10=4n+10 minus 4n both sides 9n-4n-10=4n-4n+10 5n-10=0+10 add 10 5n+10-10=0+10+10 5n+0=20 5n=20 divide both sies by 5 5n/5=20/5 5/5n=4 1n=4 n=4