You have the following expression:
5l-6 +2l - 8
In order to simplify the previous expression, first consider that the absolute value of any number, positive or negative, is the positive number, then, you have:
l- 6 + 2l = l-4l = 4
Replace the previous result into the given expression and simplify:
5(4) - 8 = 20 - 8 = 12
Hence, the simplified expression is equal to 12