To find out what must be subtracted from 3 to get 9, we can set up the equation:
3 – x = 9
Here, x represents the number that we need to find. To isolate x, we can rearrange the equation:
-x = 9 – 3
-x = 6
Now, to solve for x, we need to multiply both sides by -1:
x = -6
This means that -6 must be subtracted from 3 to arrive at 9. In other words, 3 minus a negative number ends up adding to the original number, resulting in a larger number like 9.