Cho hai biểu thức A=[0,25X7+(0,25)^2](0,4.5^2-2/5)

* Hướng dẫn giải

$\begin{array}{l}A=\left[0,25\times 7+{\left(0,25\right)}^2\right]\left(0,4\times 5^2-\frac{2}{5}\right)\\ A=\left(\frac{7}{4}+\frac{1}{16}\right).\left(\frac{2}{5}.25-\frac{2}{5}\right)\\ A=\frac{29}{16}.\frac{48}{5}\\ A=\frac{87}{5}=17\frac{2}{5}\end{array}$

$\begin{array}{l}B=\left(\frac{2}{89}-\frac{3}{178}\right)\cdot \frac{89}{17}+\frac{33}{34}\\ B=\left(\frac{4}{178}-\frac{3}{178}\right).\frac{89}{17}+\frac{33}{34}\\ B=\frac{1}{178}.\frac{89}{17}+\frac{33}{34}\\ B=\frac{1}{34}+\frac{33}{34}=1\end{array}$

Vậy A>B