Find Value of Given Equation

If 999x + 888y = 1332 and 888x 999y =555, then X2  – y2  equal is

  1. 8
  2. 9
  3. 5
  4. 7
Manish Listener Asked on 15th June 2015 in Maths.
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1 Answer(s)

Answer: (4) 7
Explanation:-
999X + 888Y = 1332
111(9X + 8Y) = 1332
9X + 8Y = 1332/111
9X + 8Y = 12               …………………(1)
And,
888X + 999Y = 555
111(8X + 9Y) = 111 x 5
8X + 9Y = 5                ………………………(2)
Solve equation (1) & (2)
Y = -3  &   X = 4
X2 – Y2 = 42 – 32
= 16  – 9 = 7
Hence, the answer is (4) 7

Anurag Mishra Professor Answered on 15th June 2015.
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