Quick way to find the solution of a linear and quadratic equation?

If you want to solve them mentally (which is perfectly possible), just practice solving them mentally ! Quadratics can sometimes be solved by factoring, but it's not too hard to memorize the quadratic formula, and to calculate the discriminant in your head.

linear : a x = b are trivial , quadratic... a x² + b x + c = 0 uses the quadratic equation

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