Respuesta :

x*(x+1) = 420
x²+x = 420
x²+x-420=0

Answer:

The quadratic equation is x² + x - 420 = 0 and value of x is 20.

Step-by-step explanation:

As given

The product of two consecutive integers is 420.

As the one consecutive number be x.

The other consecutive number be x + 1.

Than the equation becomes

x (x + 1 ) = 420

x² + x = 420

x² + x -420 = 0

x² + 21x - 20x - 420 = 0

x (x + 21) - 20 (x + 21) = 0

(x - 20) (x + 21) = 0

As  x = 20  and x = - 21

The value x = -21 (Neglected because x + 1 = -21 +1 = -20 , becomes smaller value.)

Than  

x = 20

Than

(x + 1)= 20 + 1

       =  21

Therefore the value of x is 20 .


 

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