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

Best would be that you find out solutions for each

Answer 2

Lets start from the first one

Answer 3

\[\large{x^2 + 4x + 4 = x^2 + 2\times 2 \times x + 2^2}\]

Compare this to:

\[\large{(a+b)^2 = a^2 + 2\times a\times b + b^2}\]