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Question
If the quadratic equation px2 − 2√5px + 15 = 0 has two equal roots then find the value of p.
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Solution
- a = p
- b = `-2sqrt5p`
- c = 15
Δ = b2 − 4ac
`(−2sqrt5p)^2−4(p)(15)=0`
`(2sqrt5p)^2 - 60p = 0`
4 × 5p2 − 60p = 0
20p2 − 60p = 0
20p(p − 3) = 0
p = 0 or p = 3
Since p = 0 would make the equation invalid, we take:
p = 3
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