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ISI Maths

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ans D.

//Explanation added

I tried in this way

x 2 + 6x + y 2 = x 2 + 2 * 3x +y 2 = x 2 + 2 * 3x +9 -9+ y 2 = (x+3) 2 + y 2 - 9 =4

 (x+3) 2 + y 2  =13

Sum of two squares is 13. Do squares should be 9 and 4

when (x+ 3) 2= 9 , x =0 , -6 and y2=4 y =2,-2      //4 ordered pairs (0,2),(0,-2),(-6,2),(-6,-2)

when (x+3)2= 4, x=-1,-5   and y2= 3,-3              // 4 ordered pairs (-1,3),(-1,-3),(-5,3),( -5,-3)

Total 8 ordered pairs.

I hope solution is clear now :)

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