IIT JEE 2009 P2 Q32

Let (x,y,z) be points with integer coordinates satisfying th esystem o fhomogeneous equations

3x-y-z=0
-3x+z=0
-3x+2y+z=0

Then the number of such points for which x2+y2+z2≤100

3 Answers

11
Subash ·

I got 6(excluding trivial)

11
rkrish ·

3x-y-z=0..............(1)

-3x+z=0..................(2)

-3x+2y+z=0..................(3)

y = 0 for all x & z

z = 3x

x2+y2+z2≤100
x2+0+(3x)2≤100
10x2≤100
x2≤10

x = 0,±1,±2,±3
y = 0,0,0,0
z = 0,±3,±6,±9

Hence , Ans : 7

1
Honey Arora ·

these are 6 values..........
0,1,2,3,6,9

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