1) -0,8а*0,45b*(-c) = 0.36abc
2) m*(-0.75n)*(-0.6k)= 0.45mnk
3)3*(1.6x-0.7y)-1.8x+0.1y= 3*1.6x - 3*0.7y -1.8x+0.1y=
= (4.8x-1.8x)+(-2.1y +0.1y)= 3x - 2y
4)-5(0.9m-1.1n)-1.5m+1.9n= -4.5m -(-5.5n )-1.5m+1.9n=
= (-4.5m-1.5m)+(5.5n+1.9n) = -6m +7.4n= 7.4n-6m