$(1+\dfrac{2}{3}-\dfrac{1}{4}).(0,8-\dfrac{3}{4})^{2}$
$=$$(\dfrac{12}{12}+\dfrac{8}{12}-\dfrac{3}{12}).(\dfrac{4}{5}-\dfrac{3}{4})^{2}$
$=$$(\dfrac{20}{12}-\dfrac{3}{12}).(\dfrac{16}{20}-\dfrac{15}{20})^{2}$
$=$$\dfrac{17}{12}.(\dfrac{1}{20})^{2}$
$=$$\dfrac{17}{12}.\dfrac{1}{400}$
$=$$\dfrac{17}{4800}$
Vậy giá trị biểu thức là $\dfrac{17}{4800}$
CHÚC BẠN HOK TỐT!!!