ajutor va rog!! e pt evaluare nationalaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaqqqqqq

a) (-6-4)-(-10+8)+(-2+9)=-10+2+7= -8+7= -1
b) [-6-(-9+2)+(-5+8)]-[-2+6-(-6+8)]
=(-6+7+3)-(-2+6-2)
=4-2
=2