Given that x and y are real numbers, let S(x, y) = x^2 – y^2. Then S(3

Question

Given that x and y are real numbers, let S(x, y) = x^2 – y^2. Then S(3, S(3, 4)) =

(A) –40
(B) –7
(C) 40
(D) 49
(E) 56

ShitakeMushroom · Answer

I choose (A)

First, I start with S(3,4).
S(3,4) = 9-16 = -7

Then, S(3,S(3,4)) = S(3,-7)
S(3,-7) = 9-49 = -40

AS20 · Answer

Given that x and y are real numbers, let S(x, y) = x^2 – y^2. Then S(3, S(3, 4)) =

Sol- To start with, S(3,4)= -7 . Putting value in exp S(3,S(3,4))= S(3,-7)= 3^2- (-7)^2= 9-49=-40. Ans - A

BrushMyQuant · Answer

Given that S(x, y) = x^2 – y^2 and we need to find the value of S(3, S(3, 4))

To find S(3, 4) we need to compare what is inside the ( ) in S(3, 4) and S(x, y)

=> We need to substitute x with 3 and y with 4 in S(x, y) =  x^2 – y^2  to get the value of S(3, 4)

=> S(3, 4) =  3^2 – 4^2  = 9 - 16 = -7

=> S(3, S(3, 4)) = S(3,-7) =  3^2 – (-7)^2  = 9 - 49 = -40

So,  Answer will be A 
Hope it helps!

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