Question

If 4 is a root of the quadratic equation x2+px 4=0 and the quadratic equation x2+px+k=0 has equal roots
find the value of K.​

Answer 1

x2+px+k=0

a=1, b=p, c=k

D=b2-4ac=0

p2- 4×1×k =0

p2- 4k =0

p2=4k

k=p2/4

I think it's correct

follow me

Answer 2

The given equation is

x2 +px + 4 = 0

Since 4 is one root of the quadratic equation so it satisfy the equation

(4)2 + 4p + 4 = 0

16 + 4p + 4 = 0

4p + 20 = 0

4p = -20

p = -5

And the quadratic equation

x2+px +k has equal roots.

So 4 satisfy the equation also the value of p satisfy the equation

(4)2 + (-5)*4 + k = 0

16 - 20 + k = 0

k - 4 = 0

k = 4

Hence the value of k is 4

Hope it helps you

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