Expanding the left side of the equation, we get:

6x(7) - 6x(3) - 2x(21x) + 2x(6) = 3 - 30x

42x - 18x - 42x^2 + 12x = 3 - 30x

Subtracting 3 from both sides:

42x - 18x - 42x^2 + 12x - 3 = -30x

Rearranging and simplifying:

-42x^2 + 36x - 3 = -30x

Adding 30x to both sides:

-42x^2 + 66x - 3 = 0

This quadratic equation is now in the form of ax^2 + bx + c = 0.