Question

By what number should $(-15{)}^{-1}$ be divided so that the quotient may be equal to $(-5{)}^{-1}$ ?

Answer 1

$Letthenumbershouldbedividedby=xtheir(-15{)}^{-1}÷x=(-5{)}^{-1}\Rightarrow \frac{1}{-15}÷x=\frac{1}{(-5{)}^1}\Rightarrow \frac{-1}{15}\times \frac{1}{x}=\frac{1}{-5}\Rightarrow \frac{-1}{15x}=\frac{1}{-5}\Rightarrow -15x=-5\Rightarrow x=\frac{-5}{-15}=\frac{1}{3}\therefore Requirednumber=\frac{1}{3}$