[tex]\displaystyle\bf\\\frac{3}{4}-\bigg(\frac{2}{5}\bigg)^2=\\\\=\frac{3}{4}-\frac{2^2}{5^2}=\\\\=\frac{3}{4}-\frac{4}{25}=~~(Aducem~la~acelasi~numitor)\\\\=\frac{^{25)}3~~}{~~~4~~}-\frac{^{4)}4~}{~~~25~~}=\\\\=\frac{75}{100}-\frac{16}{100}=\\\\=\frac{75-16}{100}=\boxed{\bf\frac{59}{100}}[/tex]
