1.
1)-5а× (-7)×(-5b)= - 155×a×b
2) -5a×(-9)×(-4b)= - 180×a×b
3)-15 c× 4 ×(-3d)= 180×c×d
4)7m×(-8)×5n = -280×m×n
5)5m × (-6)×(-20n)=600mn
6)125m × 7 × (-9n)= -7875mn
2.
1)-0.2× (-5)×13= 1×13=13
2)-2,5×4×(-1,3)= (-10)×(-1,3)=13
3)-0,25×(-4)×(-0,3)=1×(-0,3)=-0,3
4)(-4)×5 ×(-7/10)= -20×(-7/10)=2×7=14
5)(-8/15)×(-1/2)×(-3/4)= (-8/15)×3/8= -3/15= -1/5= -0,2
6)-3/4×4×(-5)= -3×(-5)=15