Question

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

Answer 1

first option is right.

Answer 2

First option.

Explanation:

For a quadratic equation of the form:

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

we have that the solutions for x are:

`x = (-b +- √(b^2 - 4ac) )/(2a)`

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:

`x = (-3 +- √(3^2 - 4*5*(-4)) )/(2*5)`

then the correct option is the first one.