# Question #7a4fb

Refer to explanation

#### Explanation:

The marginal rate of technical substitution can be defined as

$M R = - \frac{\frac{\mathrm{df}}{\mathrm{dx}} _ 1}{\frac{\mathrm{df}}{\mathrm{dx}} _ 2} = - \frac{\frac{3}{4} \cdot {\left({x}_{1}\right)}^{- \frac{1}{4}} \cdot {\left({x}_{2}\right)}^{\frac{1}{4}}}{{\left({x}_{1}\right)}^{\frac{3}{4}} \cdot \left(\frac{1}{4}\right) \cdot {\left({x}_{2}\right)}^{- \frac{3}{4}}} = - 3 \cdot \frac{{x}_{2}}{{x}_{1}}$