To complete the square:
we take the coefficient ox "x" (which in this problem is -20)
we divide it by 2
square that number
then add it to both sides of the equation
-20 / 2 = -10
-10^2 = 100
then we add 100 to both sides of the equation:
x^2 -20x
x^2 -20x +100 = 100
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To get the roots of the equation, we take the square root of both sides:
(x -10) * (x-10) = 10
(x-10) = square root (10)
x-10 =
3.1622776602
x1 =
13.1622776602
and don't forget that square root of 10 also equals -3.1622776602
x2 = 10
-
3.1622776602
x2 =
6.8377223398
