Question

Anyone help me. ....​

Answer 1

see explanation

Explanation:

Using the rules of exponents

All the exponents inside the parenthesis are multiplied by the exponent outside the parenthesis.

Then

`(m^(-7)n^(14) )/(m^(-25)n^(40) )` ÷
`(m^(-21)n^(42) )/(m^(-25)n^(40) )`

[ Using the rule
`(a^(m) )/(a^(n) )` =
`a^((m-n))` ]

=
`m^((-7-14))`
`n^((14-(-28))` ÷
`m^((-15-10))`
`n^((25-(-15))`

=
`m^(-21)`
`n^(14+28)` ÷
`m^(-25)`
`n^(25+15)`

=
`(m^(-21)n^(42) )/(m^(-25)n^(40) )`

=
`m^((-21-(-25)))`
`n^((42-40))`

=
`m^((-21+25))` n²

=
`m^(4)` n² =
`m^(x)`
`n^(y)` , so x = 4 and y = 2

Then

`m^(x-2y)` =
`m^(4-2(2))` =
`m^(4-4)` =
`m^(0)` = 1 ← as required