Subtract the constant term ca from both sides. It makes a parabola a U shape when graphed on a coordinate plane. So it will have something like x2.
When people work with quadratic equations one of the most common things they do is to solve it.
A Quadratic Equation is one that can be written in the standard form ax2 bx c 0 where a b and c are real numbers and a does not equal zero. This completes the square converting the left. A quadratic equation has two solutions called roots. Subtract the constant term ca from both sides.