Question

If the equation px2 + 15 - 2√5x = 0 has two equal roots which of the following is the value
of p.
a.3
b.-1
c.0
d.1/3​

Answer 1

Answer:

here a=p b=-2√5 and c=15

for equla roots

D=b^2-4ac=0

so

(-2√5)^2-4p*15=0

4*5=4*p*15

=> p=4*5/(4*15)

=> p=1/3

there fore p=1/3

so option d. 1/3 is correct.

Answer 2

Answer:

(a) 3

Step-by-step explanation:

If in equation ax^2+bx+c=0 the two roots are equal.

Then b^2 −4ac=0

In equation px^2 −2√5px+15=0

a=p,b=−2√5p and c=15

Then b^2 −4ac=0

⇒(−2√5p)^2−4×p×15=0

⇒20p^2−60p=0

⇒20p(p−3)=0

So when p−3=0⇒p=3

p is not equal to 0 as it makes coefficient of x^2=0

Hence, p=3