-2,5a×1,2×(-4b)= 8×(-3x)×0,25y= 7x-5x+3x= -9-y+13-8y= 15a-2b-4a+9b= 4c-5b+7c-6b=
1) 12аb 2)-6xy 3)(7-5+3)x=5x 4)4-9y 5)11a+7b 6)11c-11b=11(c-b)