= Root of an equation
= Roots of an equation
{synonym}
= equation root
{synonym}
A <root of an equation> is a value of its unknown that makes the equation true. For an equation $f(x)=0$, it is a <zero of a function>. More generally, roots of $f(x)=g(x)$ are zeros of $f-g$, provided both sides are defined at the candidate value.
For example, $x^2=4$ has the real roots $2,-2$. Clearing a denominator requires checking the original <domain>: solving $(x^2-1)/(x-1)=0$ permits $x=-1$ but not $x=1$. The coefficient <field> also matters, since $x^2+1=0$ has no real root but has two complex roots.
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