Question

What number must you add to complete the square? x2 - 20x = 17

Answer 1

The answer is 100 ;) 

Answer 2

Answer:

To complete the square:

1) Move the "non X" term to the right:

(Already done)

2) Divide the equation by the coefficient of X² which in this case is 4

(Already done)

then:

• take the coefficient of X

-20

• divide it by 2

-10

• square that number

100

• then add it to both sides of the equation.

So, the answer is A 100

Source:

http://www.1728.org/quadr2.htm