You need to subtract everything to the left side and set it equal to zero. Combine like terms.
Then, the coefficient of x^2 is a, the coefficient of x is b, and the constant term is c.
4x^2 - 5 = 3x + 4
4x^2 - 3x - 5 - 4 = 0
4x^2 - 3x - 9 = 0
a = 4; b = -3; c = -9