Since 7-(-11) is in absolute value you have to change it to 7-11
In absolute value a positive is a positive and a negative is a positive.
When subtracting a smaller number from a bigger number you have to remember that it will always be negative. So just subtract 11 from 7 and add a negative sign.
11-7=4 so 7-11=-4.
If it wasn't in absolute value it would be different.
I hope that helps!