Question

Which of the following equations has only one solution?
x 2 + 4x + 4 = 0
x 2 + x = 0
x 2 - 1 = 0

Answer 1

the one that is a perfect square

Answer 2

what do you know from dixcriminant property ?

Answer 3

the second one is a perfect square

Answer 4

can you answer my question please ?

Answer 5

idk

Answer 6

no actually the second one is not a perfect square
\[x^2+4x+4=(x+2)^2\]
\[x^2+x=x(x+1)\]
\[x^2-1=(x+1)(x-1)\]

Answer 7

how do you know when the discriminant of one equation is equal zero what sign this for sulutions of this equation ?