Which equation shows the quadratic formula used correctly to solve 5x^2+3x-4=0

x = sqrt (89) / 10 - 3/10 or x = - 3/10 - sqrt (89) / 10

Step-by-step explanation:

Solve for x over the real numbers:

5 x^2 + 3 x - 4 = 0

Divide both sides by 5:

x^2 + (3 x) / 5 - 4/5 = 0

Add 4/5 to both sides:

x^2 + (3 x) / 5 = 4/5

Add 9/100 to both sides:

x^2 + (3 x) / 5 + 9/100 = 89/100

Write the left hand side as a square:

(x + 3/10) ^2 = 89/100

Take the square root of both sides:

x + 3/10 = sqrt (89) / 10 or x + 3/10 = - sqrt (89) / 10

Subtract 3/10 from both sides:

x = sqrt (89) / 10 - 3/10 or x + 3/10 = - sqrt (89) / 10

Subtract 3/10 from both sides:

Answer: x = sqrt (89) / 10 - 3/10 or x = - 3/10 - sqrt (89) / 10