Answer:
[tex]\boxed{\dfrac{16y^{4}}{7x^{4}}}[/tex]
Step-by-step explanation:
Your expression is
[tex]\dfrac{(7x^{2}y^{-2})^{-1}}{(4x^{-1}y)^{-2}}[/tex]
1. Handle the outer exponents
Remember that x⁻¹ = 1/x . Then
[tex]\dfrac{(7x^{2}y^{-2})^{-1}}{(4x^{-1}y)^{-2}} = \dfrac{(4x^{-1}y)^{2}}{7x^{2}y^{-2}}[/tex]
2. Square the numerator
When you square a number, you multiply its exponent by 2.
[tex]\dfrac{(4x^{-1}y)^{2}}{7x^{2}y^{-2}} = \dfrac{4^{2}x^{-2}y^{2}}{7x^{2}y^{-2}}[/tex]
3. Divide like terms
[tex]\dfrac{4^{2}x^{-2}y^{2}}{7x^{2}y^{-2}} = \left ( \dfrac{16}{7}\right)\left (\dfrac{x^{-2}}{x^{2}}\right )\left (\dfrac{y^{2}}{y^{-2}}\right )[/tex]
4. Evaluate each term
When you divide numbers with exponents, you subtract the exponent in the denominator from that in the numerator
[tex]\left ( \dfrac{16}{7}\right)\left (\dfrac{x^{-2}}{x^{2}}\right )\left (\dfrac{y^{2}}{y^{-2}}\right ) = \left ( \dfrac{16}{7}\right)\left (\dfrac{x^{-4}}{1}\right )\left (\dfrac{y^{4}}{1}\right )[/tex]
5. Move x to the denominator and combine terms
[tex]\left ( \dfrac{16}{7}\right)\left (\dfrac{x^{-4}}{1}\right )\left (\dfrac{y^{4}}{1}\right ) =\mathbf{ \dfrac{16y^{4}}{7x^{4}}}\\\\\text{The simplified expression with positive exponents is } \boxed{\mathbf{\dfrac{16y^{4}}{7x^{4}}}}[/tex]