Question

Add and simplify.20(Type an integer or a simplified fraction.)

Answer 1

$-\dfrac{7}{20}+\left(-\dfrac{9}{20}\right)=\dfrac{-7}{20}+\dfrac{-9}{20}=\dfrac{-7+(-9)}{20}=\dfrac{-16}{20}=-\dfrac{16:4}{20:4}=\boxed{-\frac{4}{5}}$