Hi there!
Let's replace "a number" by "x":
- two times x = 2x
- decreased by 3 = -3
Here's what the equation should look like:
2x - 3 = 11
Now that you have written down your equation, all you have to do now is solve it for "x" by isolating it :
2x - 3 = 11
Add 3 on each side of the equation
2x = 14
Divide each side of the equation by 2
x = 7
Your answer is: The number is 7.
There you go! I really hope this helped, if there's anything just let me know! :)