Bài 1: (2,0 điểm) Thực hiện phép tính: a) $\frac{13}{50}$.(-15,5) - $\frac{13}{50}$.84$\frac{1}{2}$ b) $\frac{2}{9}$ + $\frac{1}{3}$ : (-$\frac{3}{2}$) + $\frac{1}{2}$.(-0,5) c) 4.(-$\frac{1}{2}$)³ - 2.($\frac{-1}{2}$)² + 3.(-$\frac{1}{2}$) + 1 d) $\frac{(-0,7)².(-5)³}{(\frac{-7}{3})^{3}.(\frac{3}{2})^{4}.(-1)^{5}}$

a) `13/50 . (-15,5) - 13/50 . 84 1/2`

`= 13/50 (-15,5 - 84,5)`

`= 0,26 . (-100)`

`= -26`

b) `2/9 + 1/3 : (-3/2) + 1/2 . (-0,5)`

`= 2/9 + 1/3 . (-2/3) + 1/2 . (-1/2)`

`= 2/9 - 2/9 - 1/4`

`= -1/4`

c) `4 . (-1/2)^3 - 2 . ((-1)/2)^2 + 3 . (-1/2) + 1`

`= 4 . (-1/8) - 2 . 1/4 + 3 . (-1/2) + 1`

`= -4/8 - 2/4 - 3/2 + 1`

`= -1/2 - 1/2 - 3/2 + 2/2`

`= -3/2`

d) `((0,7)^2 . (-5)^3)/(((-7)/3)^3 . (3/2)^4 . (-1)^5)`

`= (0,49 . (-125))/(-216/27 . 81/16 . (-1))`

`= (-245/4)/(1029/16)`

`= -245/4 . 16/1029`

`= -20/21`