Lets say the number is x. The formula would be: 2x + x - 18 = x -30 To find x, you have to get rid of everything els, so minus x from both sides. 2x - 18 = -30 Since -30 is the smallest number, you get rid of that next. Add 30 to both sides 2x + 12 = 0 Now get rid of +12 by doing -12. 2x = -12 divide both sides by 2 to get x by itself x = -6.
To double check your answer, do the reverse. Substitute -6 iinto the equation wherever it says x.
2x + x - 18 = x -30 becomes (2 x -6) + (-6 - 18) = -6 - 30. Use BIDMAS (Brackets Indices Division Multiplication Addition Subtraction) to get your answer. Brackets are first -12 + -24 = -6 - 30 -36 = -6 - 30 which is basically -36 = -36
