формула куба помогите решить-------1-(4a+1/3b)^3 2-(2x-1/2y)^3 3-(2/3x-3y)^3 4-(1/3m+1/2n)^3

(a+b)=a+3ab+3ab+b
(a-b)=a-3ab+3ab-b

 (4а+1/3 b)=64a + 3*16a *1/3 b + 3*4a * 1/9b + 1/27b=64a + 16ab + 4/3 ab + 1/27 b
  
 (2x-1/2y)=8x - 2xy +1/2 ay - 1/8 y

(2/3 x - 3y)=8/27 x - 4/3 xy+6xy - 27y

(1/3 m+1/2 n)=1/27 m+1/18 mn+1/12 mn+1/8 n

(1/5 a+5b)=1/125 a +1/5 ab+5ab+125b