How do you solve x^2-4x=10 by completing the square?

1 Answer
bp
May 17, 2015

Solution is x=2+-sqrt14

To make a perfect square on the left side, take half the coefficient of x and then square it. Here half of -4 is -2 and its square would be 4. Now add this number on both sides of the equation. On the left side it would now be a perfect square.

x^2 -4x+4= 10+4

(x-2)^2 =14

x-2=+-sqrt14

x=2+-sqrt14

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