Solve the Equation: 20:x·(-4)=-80 with Ratio Notation

Maintaining the question mark let's proceed to write the exercise as follows:

$\frac{20}{?}\times-4=-80$

Divide by negative 4:

$\frac{20}{?}\times\frac{-4}{-4}=\frac{-80}{-4}$

Break down the 80 into a multiplication exercise:

$\frac{20}{?}\times\frac{-4}{-4}=\frac{20\times-4}{-4}$

Due to the fact that we are dividing two negative numbers the result must be a positive number:

$\frac{20}{?}\times\frac{4}{4}=\frac{20\times4}{4}$

Let's now reduce the 4 in both the numerator and denominator of the fraction and we should obtain the following:

$\frac{20}{?}\times1=20$

Multiply by the question mark:

$20=20\times\text{?}$

Divide by 20:

$\frac{20}{20}=?$

$1=\text{?}$