Question

Equation $a{x}^2+2x+1$ has one double root if:

• A. a = 0
• B. a = -1
• C. a = 1
• D. a = 2

Answer 1

The correct option is C a = 1

One double root means a single root appears two times i.e., two roots are equal.
$\therefore D=0\Rightarrow (2{)}^2-4a.1=0\Rightarrow a=1.$