What is the value of 10x^-3y^-1 for x=-1 and y=-3? a. 10(3)^-4 b. 30 c. 10/81 d. 3 1/3

The correct answer is:  [D]:  " 3  " .
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Explanation:
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Given:  "  10x⁻³ y⁻¹ " ;  

Evaluate when:  " x = -1 " ; and when " y = -3 " ; 

→  10 * (-1)⁻³ * (-3)⁻¹ = ?

Note:  " (-1)⁻³  =  (1 / (-1)³ = 1 / (-1 * -1 * -1) = 1/ -1 = -1 " ; 

     →  " (-1)⁻³  =  -1  " ; 

     → "  (-3)⁻¹  =  1 / (-3)¹ = 1 / -3 ;  = - 1/3 ; 

→  " 10x⁻³ y⁻¹  =  10 * (-1) * ( - 1/3) ; 

                        =  -10 * (- 1/3) =  (-10/1) * (-1/3) = (-10 * -1) / (1 * 3)  = 10/3;

→ 10/3 = 10 ÷ 3 = " 3 " ;
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     →  which is:  Answer choice:  [D]:  " 3 " .
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