Answer :
3)distributive property
Robert had given 3 to each term. which then results in 3x+6=21. Then. if he further went on, you would subtract 6 from each side giving you 15 then divide 15 by 3 giving you x=5.
Robert had given 3 to each term. which then results in 3x+6=21. Then. if he further went on, you would subtract 6 from each side giving you 15 then divide 15 by 3 giving you x=5.