The goal of this problem is to solve the equation by completing the square.

x^2 - 13 x + 36 = 0

Question

The goal of this problem is to solve the equation by completing the square.

x^2 - 13 x + 36 = 0

helder_edwin · Answer

first add -36 to both sides

anonymous · Answer

Right, that I understand. I'm just finding it hard to think of a perfect square which would involve -13.

helder_edwin · Answer

then u got
$$ \large x^2-13x+\qquad=-36 $$

helder_edwin · Answer

in the blank: put the coefficient of x (-13) halved and then squared and add the same to the right hand side

anonymous · Answer

x^2-13x+169/4=25/4

anonymous · Answer

Right?

helder_edwin · Answer

u forgot the -36 on the RHS
$$ \large x^2-13x+\color{red}{\frac{169}{4}}=-36+\color{red}{\frac{169}{4}}=
    \frac{25}{4} $$

helder_edwin · Answer

sorry u forgot nothing.

helder_edwin · Answer

factor the LHS

anonymous · Answer

Alright. So, (x-13/2) = 25/4?

anonymous · Answer

Sorry...the LHS should be squared.

helder_edwin · Answer

yes. u r right

anonymous · Answer

Okay, wonderful. So...is the sol'n 13/2 plus or minus sqrt(25/4)?

helder_edwin · Answer

yes
$$ \large x=13/2\pm\sqrt{25/4} $$

anonymous · Answer

Okay, wonderful. Thanks so much!!

helder_edwin · Answer

u r welcome