How Would I Simplify (-r+s)(-r-s)?

(-)(-) = +
(-)(+) = -
(+)(-) = -
(+)(+) = +

Solving the brackets you will get
= (-r)(-r) + (-r)(-s) +(s)(-r) + (s)(-s)

Applying the above mentioned rules
= r^2 + rs - rs - s^2
= r^2 - s^2 >>answer

Or simply you can also apply formula

(a+b)(a-b) = (a^2 -b^2)
(-r+s)(-r-s) = r^2 - s^2

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