Выражения: 1)15а*(-6b)= 2)-4m-15n+3m+18n= 3)b+(7--b)= 4)-2(x-3)+4(x+1)=

1)15а*(-6b)=-90ав   
2)-4m-15n+3m+18n=-4m+3m-15n+18n=-m+3n

3)b+(7-b)-(14-b)=b+7-b-14+b=b-7

4)-2(x-3)+4(x+1)=-2x+6+4x+4=2x+10

1) 15а * (-6b) = -90ab
2) -4m - 15n + 3m + 18n = -m + 3n
3) b + (7 - b) - (14 - b) = b + 7 - b - 14 + b = -7 + b
4) -2(x - 3) + 4(x + 1) = -2x + 6 + 4x + 4 = 2x +10