Tính a) (-0,4)^2 - (-0,4)^3 .(-3) b) (1 3/4)^3 - (1 3/4)^2 + (-1,031)^0

* Hướng dẫn giải

a) ${\left(-0,4\right)}^2-{\left(-0,4\right)}^3.\left(-3\right)={\left(-\frac{4}{10}\right)}^2-{\left(-\frac{4}{10}\right)}^3.\left(-3\right)=\frac{4}{25}-\frac{8}{125}.3=\frac{-4}{125}$

b) ${\left(1\frac{3}{4}\right)}^3-{\left(1\frac{3}{4}\right)}^2+{\left(-1,031\right)}^0={\left(1\frac{3}{4}\right)}^2\left(1\frac{3}{4}-1\right)+1$$={\left(\frac{7}{4}\right)}^2\left(\frac{7}{4}-1\right)+1=\frac{49}{16}.\frac{3}{4}+1=\frac{211}{64}$