## Basic College Mathematics (9th Edition)

$\dfrac{2}{5}-\dfrac{7}{10}+\Big(-\dfrac{3}{2}\Big)=-\dfrac{9}{5}$
$\dfrac{2}{5}-\dfrac{7}{10}+\Big(-\dfrac{3}{2}\Big)$ First, evaluate the subtraction $\dfrac{2}{5}-\dfrac{7}{10}$: $\dfrac{2}{5}-\dfrac{7}{10}+\Big(-\dfrac{3}{2}\Big)=\dfrac{4-7}{10}+\Big(-\dfrac{3}{2}\Big)=-\dfrac{3}{10}+\Big(-\dfrac{3}{2}\Big)=...$ Take out common factor $-1$: $...=-\Big(\dfrac{3}{10}+\dfrac{3}{2}\Big)=...$ Evaluate the sum inside the parentheses and simplify: $...=-\Big(\dfrac{3+15}{10}\Big)=-\Big(\dfrac{18}{10}\Big)=-\dfrac{9}{5}$