Which equation shows the quadratic formula used correctly to solve 5x2 + 3x – 4 = 0 for x?

First option.

Step-by-step explanation:

For a quadratic equation of the form:

a*x^2 + b*x + c = 0

we have that the solutions for x are:

where we have two solutions, one for each sign of the square root.

then if our equation is:

5x^2 + 3x - 4 = 0

we have that 5 = a, 3 = b and -4 = c, then our equation is:

then the correct option is the first one.

-3.396 = -3.4

-0.708 = -0.7

0.304 = 0.3

0.955 = 1