Question 321782
Identify the numbers that needs to be added to both sides of the equation x^2 - 4x +21 to complete the square. 
a. 6
b. 3
c. 4
d. 21
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1st, it's not an equation, there's no equal sign.
If you make it = 0, then
x^2 - 4x +21 = 0
You have to add -17 to both sides.