$x^2 - 25 = 0$ $x^2 = 25$ $x = \pm 5$
$0.2x^2 + 7.2 = 0$ $0.2x^2 = -7.2$ $x^2 = -36$ No real solutions.
$-7x^2 + 28 = 0$ $-7x^2 = -28$ $x^2 = 4$ $x = \pm 2$
$-4x^2 + 1 = 0$ $-4x^2 = -1$ $x^2 = \frac{1}{4}$ $x = \pm \frac{1}{2}$
$-0.8x^2 - 9.2 = 0$ $-0.8x^2 = 9.2$ $x^2 = \frac{9.2}{0.8} = 11.5$ $x = \pm \sqrt{11.5}$
$-0.1x^2 + 10 = 0$ $-0.1x^2 = -10$ $x^2 = 100$ $x = \pm 10$
$x^2 - 25 = 0$
$x^2 = 25$
$x = \pm 5$
$0.2x^2 + 7.2 = 0$
$0.2x^2 = -7.2$
$x^2 = -36$
No real solutions.
$-7x^2 + 28 = 0$
$-7x^2 = -28$
$x^2 = 4$
$x = \pm 2$
$-4x^2 + 1 = 0$
$-4x^2 = -1$
$x^2 = \frac{1}{4}$
$x = \pm \frac{1}{2}$
$-0.8x^2 - 9.2 = 0$
$-0.8x^2 = 9.2$
$x^2 = \frac{9.2}{0.8} = 11.5$
$x = \pm \sqrt{11.5}$
$-0.1x^2 + 10 = 0$
$-0.1x^2 = -10$
$x^2 = 100$
$x = \pm 10$