Three times the sum of a number and 4 is the same as 18 more than the number

First, figure out what you do and don't know
You do know that 3 times the sum of a number and 4 is 18 more than the numberyou don't know the number so you make it the variable x 
now take 3 times the sum of a number and 4 and make that an expression 3x+4 this expression is the same or equal to the sum of x and 18 x+18
3x+4=x+18
2x+4=18
2x=14
x=7
hope this helped :)
         

The correct answer will be d. -4