Respuesta :

Answer:

x=6+2√3 or x=6−2√3

Step-by-step explanation:

Let's solve your equation step-by-step by using completing the square.    

5x^2−57x=3x−120

Step 1: Subtract 3x from both sides.

5x^2−57x−3x=3x−120−3x

5x^2−60x=−120

Step 2: Since the coefficient of 5x^2 is 5, divide both sides by 5.

5x2−60x/5 = −120 /5

x2−12x=−24

Step 3: The coefficient of -12x is -12. Let b=-12.

Then we need to add (b/2)^2=36 to both sides to complete the square.

Add 36 to both sides.

x2−12x+36=−24+36

x2−12x+36=12

Step 4: Factor left side.

(x−6)2=12

Step 5: Take square root.

x−6=±√12

Step 6: Add 6 to both sides.

x−6+6=6±√12

x=6±√12

x=6+2√3 or x=6−2√3