Упростите выражение и найдите его значение! =3

1) 2(а - 3b) + 3a + b = 2a - 6b + 3a + b = 5a - 5b = 5(a-b) = 5 * 4 = 20
2) 4(0,3x - 2y)+ 7,8x - y = 1,2x -8y + 7,8x - y= 9x-9y=9(x-y)=9*0,5 =4,5
3) 3(2c - 3d) +2(2,5c - d) = 6c -9d + 5c -2d =11c-11d =11(c-d) = 11*3 = 33
4) 5(3x +y) +2(7x +12y) = 15x +5y+14x+24y= 29x + 29y=29(x+y) = 29*1=29