A quadratic equation is an equation of the form
ax2 + bx + c = 0.
In other words, it's an equation that sets a quadratic polynomial equal to zero. Got that? On the left side of the equals sign, a quadratic polynomial, and on the right side...well, there ain't no thang.
We've solved some quadratic equations already by factoring to find the roots of the quadratic polynomial. Now we'll dive more deeply and learn how to solve quadratic equations that can't be easily factored. Don't go too fast or you'll get the bends.