second option.
Step-by-step explanation:
Let be "x" the unknown number.
According to the information provided in the exercise, 10 is the result of the subtraction of "x" and -5.
Based on this, you can write the following equation:
![x-(-5)=10](/tpl/images/0189/6929/f0ad1.png)
To find the value of "x" you must remember the multiplication of signs:
![(+)(+)=+\\(-)(-)=+\\(-)(+)=-](/tpl/images/0189/6929/fe80e.png)
Then:
![x-(-5)=10\\\\x+5=10](/tpl/images/0189/6929/9c8c5.png)
Finally, subtracting 5 from both sides of the equation, you get:
![x+5-(5)=10-(5)\\\\x=5](/tpl/images/0189/6929/808f2.png)