(2) solution: the original formula =(-3/4)X(- 1 you 1/2)÷(-2 you 1/4).
=-3/4×(-3/2)×(-4/9)=- 1/2
(3) Solution: The original formula =(-7)X(-56)X0÷(- 13)=0.
(4) Solution: The original formula =-9x (-11) ÷ 3 ÷ (-3) =-1.
I made it myself. If I am wrong, don't blame me.