Question

if the equation ax^2+bx+c has equal roots then c=

a)-b/2a
b)b/2a
c)-b^2/4a
d)b^2/4a

Answer 1

We already know that if a quadratic equation ax^2+bx+c = 0 has real and equal roots then :

b^2 - 4 ac = 0

So, b^2 - 4 ac = 0

or, - 4 ac = - b^2

or, c = b^2/4a [OPTION D]