How do you solve x^2-24x=10x224x=10 by completing the square?

2 Answers
Oct 22, 2017

x = 24.4097, -0.4097x=24.4097,0.4097

Explanation:

x^2 -24x = 10x224x=10

x^2 + (2 (x) (-12) ) = 10 x2+(2(x)(12))=10

x^2 + ( 2 (x) (-12) ) +144 -144 = 10x2+(2(x)(12))+144144=10 (Add and subtract 144)#

x^2 + ( 2 (x)(-12) + (12)^2 = 154x2+(2(x)(12)+(12)2=154
(x-12)^2 = 154(x12)2=154
(x-12) = +-sqrt 154 color (white)(aaa)(x12)=±154aaataking square root on both sides
x = 12 +- sqrt154 x=12±154
x = 24.4097, -0.4097x=24.4097,0.4097

Oct 22, 2017

x=12+-sqrt(154)x=12±154

Explanation:

Completing the square means making the x^2x2 and xx terms take the form x^2 +2nx +n^2x2+2nx+n2. Where in this case n=-12n=12.

So, x^2-24x=10x224x=10 becomes x^2 -24x+144=10+144x224x+144=10+144.
So, (x-12)^2=154(x12)2=154
x=12+-sqrt(154)x=12±154