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There are several ways to solve quadratic equations (including factoring and completing the square), but the most straightforward is the quadratic formula. Given a quadratic in the form $$ax^2 + bx + c = 0$$, we have:

$x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}.$

Thus for the quadratic $$2x^2 - 22x + 20 = 0$$, we have

$x = \frac{22 \pm \sqrt{22^2 - 4(2)(20)}}{2(2)} = \frac{22 \pm \sqrt{324}}{2(2)} = \frac{11 \pm 9}{2}$

Note by Arron Kau
2 years, 7 months ago