Question

Consider the quadratic equation below.

Answer 1

The right answer is the 2nd one.

It's using the quadratic equation

Answer 2

You are given the quadratic  4x^2 - 5 = 3x + 4.  You cannot apply the quadratic formula until this has been rewritten in the form y = ax^2 + bx + c.  After re-arranging the terms, we get 

4x^2 - 3x - 9 = 0.  Then a=4, b= -3 and c= -9.  

Then:
        3 plus or minus sqrt(9-4(4)(-9)
x = ------------------------------------------
                    2(4)