3x²-6x-72. The quadratic equation whose roots are -4 and 6 with a leading coefficient of 3 is 3x²-6x-72.
The solutions of a quadratic equation are x = -4 and x = 6 with a leading coefficient of 3. The solutions are two real numbers which means that (x + 4) and (x - 6) are the factors of our unknown quadratic equation and the leading coefficient is 3.