How do you solve x^2-5x=-4x2−5x=−4 by completing the square?

1 Answer
Massimiliano
Apr 30, 2015

In this way:

x^2-5x=-4rArrx^2-5x+25/4-25/4=-4rArrx2−5x=−4⇒x2−5x+254−254=−4⇒

(x-5/2)^2=25/4-4rArr(x-5/2)^2=(25-16)/4rArr(x−52)2=254−4⇒(x−52)2=25−164⇒

(x-5/2)^2=9/4rArrx-5/2=+-3/2rArrx=5/2+-3/2rArr(x−52)2=94⇒x−52=±32⇒x=52±32⇒

x_1=5/2-3/2=1x1=52−32=1

x_2=5/2+3/2=4x2=52+32=4.

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