solve the equation7x+21=105
remmeber you can do anything to an equaiton as long as you do it ot both sidesisolate placeholder7x+21=105subtract 217x+21-21=105-217x+0=847x=84divide both sides by 77x/7=84/7x=12
x = 12 all you have to do is subtract 21 from 105 your answer would be 84 then you would do 84 divided by 7 and the answer would be 12 so x equals 12
