SOLUTION: solve by completing the square to obtain exact solutions? x square -3x = 18 x2-3x=18

Question 70104: solve by completing the square to obtain exact solutions?
x square -3x = 18
x2-3x=18
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
solve by completing the square to obtain exact solutions?
x square -3x = 18
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x^2-3x=18
Divide the coefficient of "x" by 2 and square the result to get the following:
Note: The sign of the coefficient makes no difference because you are going to
square the result.
x^2-3x+(3/2)^2=18+(3/2)^2
Factor the left side and simplify the right side:
(x+(3/2))^2= 18+(9/4)
(x+(3/2))^2 = 81/4
Take the square root of both sides to get:
x+(3/2)= 9/2 or x+(3/2)= -(9/2)
x=3 or x=-6
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Cheers,
Stan H.
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