X2+2x+1=0 solve equation

This equation

In algebra, a **quadratic equation** (from the Latin *quadratus* for “square“) is any equation having the form

{displaystyle ax^{2}+bx+c=0}

where *x* represents an unknown, and *a*, *b*, and *c* represent known numbers such that *a* is not equal to 0. If *a* = 0, then the equation is linear, not quadratic. The numbers *a*, *b*, and *c* are the *coefficients* of the equation, and may be distinguished by calling them, respectively, the *quadratic coefficient*, the *linear coefficient* and the *constant* or *free term*.[1]

Because the quadratic equation involves only one unknown, it is called “univariate“. The quadratic equation only contains powers of *x*that are non-negative integers, and therefore it is a polynomial equation, and in particular it is a second degree polynomial equation since the greatest power is two.