You can put this solution on YOUR website!
Let the first number be = x
The second number is = 3+x
The third number is = 6+x
Their sum is 57.
So the equation now becomes:
I'll let you take it from here.
All you need to do now is solve for x.
Remember to check your answer by plug in the x value in the original equation.
Both sides must equal to each other. :)