Question

If the quadratic equation px² − 2√5px + 15 = 0 has two equal roots then find the value of p.

Answer 1

a = p

b = `-2sqrt5p`

c = 15

Δ = b² − 4ac

`(−2sqrt5​p)^2−4(p)(15)=0`

`(2sqrt5p)^2 - 60p = 0`

4 × 5p² − 60p = 0

20p² − 60p = 0

20p(p − 3) = 0

20p = 0

`p = 0/20`

p = 0 or p

p = 0 

p - 3 

Since p = 0 would make the equation invalid, we take:

p = 3