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प्रश्न
Choose correct alternatives:
If the equation 4x2 + hxy + y2 = 0 represents two coincident lines, then h = _______
विकल्प
± 2
± 3
± 4
± 5
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उत्तर
If the equation 4x2 + hxy + y2 = 0 represents two coincident lines, then h = ± 4.
Explanation:
ax2 + 2hxy + by2 = 0
a = 4, h = `"h"/2`, b = 1
h2 − ab = 0
`("h"/2)^2 - 4 xx 1 = 0`
`"h"^2/4 = 4`
h2 = 16
h = ± 4
Notes
The answer in the textbook is incorrect.
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