Quadratic equations part four

Here is a simple quadratic equation of the form $ax^2 + bx + c = 0$ with $a = 1$ , $b = 0$ and $c = -4$

$x^2 - 4= 0$

We can rearrange the equation to solve it for $x$

$x^2 - 4= 0$

$x^2 = 4$

$sqrt{x^2} = pmsqrt{4}$

$x = pm2$

Here is a graph of $y = x^2 - 4$

You can see that when $y = 0$ , the curve crosses the $x$ axis. This happens twice, when $x = 2$ and when $x = -2$ .

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