[tex]-0.75-\left(-\dfrac{2}{5}\right)+0.4+\left(-\dfrac{3}{4}\right)=-0.75+\dfrac{2}{5}+0.4-\dfrac{3}{4}\\\\=-0.75+\dfrac{2\cdot2}{5\cdot2}+0.4-\dfrac{3\cdot25}{4\cdot25}=-0.75+\dfrac{4}{10}+0.4-\dfrac{75}{100}\\\\=-0.75+0.4+0.4-0.75=-(0.75+0.75)+(0.4+0.4)\\\\=-1.5+0.8=-0.7[/tex]
