Relation between Roots and Coefficients for Quadratic
If p2-q2x2+...
Question
If (p2−q2)x2+(q2−r2)x+r2−p2=0 and (p2−q2)y2+(r2−p2)y+q2−r2=0 have a common root for all real values of p, q and r, then find the common root.
A
-1
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B
1
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C
2
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D
-2
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Solution
The correct option is A 1
(p2−q2)x2+(q2−r2)x+(r2−p2)=0 ....(1)
The sum of the coefficients (p2−q2)+(q2−r2)+(r2−p2)=0
Therefore, x=1 is a root of equation1.
(p2−q2)y2+(r2−p2)y+q2−r2=0 .....(2)
p2−q2+r2−p2+q2−r2=0
Therefore,
y=1 is a root of equation 2.
Therefore, 1 is the common root of equations 1 and 2.