If using the method of completing the square to solve the quadratic equation x^2+5x+10=0x 2 +5x+10=0, which number would have to be added to "complete the square"?

Respuesta :

Answer:

(5/2)² must be added to the equation to complete the square.

Step-by-step explanation:

The given equation is

x^2+5x+10=0

writing it in in square form

(x)² + 2(x) (5/2) + (5/2)²-(5/2)² + 10= 0

We multiply (5/2) to the mid term because we have to make 2x equal to 5x.

As the square formula tells that square of first element plus 2 into first element multiplied by second element plus square of second element.

Making 2x equal to 5x gives (5/2) as the second element.

Therefore add square of the second element but also subtract square of second element to make it equal to the given original equation.

Now we can solve it.

(x)² + 2(x) (5/2) + (5/2)²-(5/2)² + 10= 0

(x + 5/2)²-(5/2)² + 10= 0

(x + 5/2)²- 25/4+ 10= 0

(x + 5/2)²- 25*5 +10*5/4*5= 0

(x + 5/2)²-  125+50/20= 0

(x + 5/2)²-  175/20= 0

(x + 5/2)²=  175/20

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