Tom has a collection of 30 cds and nita has a collection of 18 cds. tom is adding 1 cd a month to his collection while nita is adding 5 cds a month to her collection. find the number of months after which they will have the same number of cds. show your work.

30 + 1x = 18 + 5x
subtract 18 from both sides
30 - 18 + 1x = 18 - 18 + 5x
12 + 1x = 5x
subtract 1x from both sides
12 + 1x - 1x = 5x - 1x
12 = 4x
To clear the multiplication by 4, divide both sides by 4
12/4 = 4x/4
3 = x
It will take 3 months until they have the same amount of CD's
They will each have 33 CD's

The surface area would be 576 because you multiply all the numbers then multiply that number by 6