In quadratic equation ax² + bx + c = 0, _____ CANNOT be zero.
In quadratic equation ax² + bx + c = 0, _____ CANNOT be zero.
Explanation
In the quadratic equation ax² + bx + c = 0, a cannot be zero.
If a = 0, the equation becomes linear (bx + c = 0), and it's no longer a quadratic equation.