∵|a-5|+b+3=0，
∴a-5=0，b+3=0，
解得a=5，b=-3．
∴a-b=5+3=8．
故答案为：8．
______well prepared you are, you still need a lot of luck in mountain climbing.
A．However
B．Whatever
C．No matter
D．Although
什么是柱网？有什么作用？
______well prepared you are, you still need a lot of luck in mountain climbing.