Call the number I am thinking of W ( for WikiAnswers)
2W+12=30
So 2W=18
W is 9
The number is 9
There is no selected number so it would be a variable. The answer is 2n-9 (n is the number which you choose)
40 + 2n
49+2x
6
15
2X + 3
There are two possible (and different) answers: 2x + 3y = 12 or 2*(x + 3y)= 12 The first one is (twice a number) increased by (three times another) The second is twice (a number increased by (three times another)).
18
Let the number be x and so the expression is: 2x+3
20+2x
2x+3
2x+15