Question 1100204
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<pre>
a.  x^2 - 8x + 9 = 0.   ====>

    x^2 - 8x = -9       ====>

    x^2 - 2*4x = -9

    x^2 - 2*4x + 4^2 = -9 + 4^2

    {{{(x-4)^2}}} = 7  ====>

    x - 4 = +/- {{{sqrt(7)}}}

    x = 4 +/- sqrt(7).
</pre>

Solved.


Regarding


<pre>
b.  2x^2 - 20x - 6 = 0


    your first step is to divide both sides by 2. Then you will get an EQUIVALENT equation

    x^2 - 10x - 3 = 0


    with the leading coefficient just 1, which will make your calculations easier.


    After that, make all the steps that I made for you in the  <U>Solution a</U>  above.
</pre>


On how to make "completing the square" see the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/Learning-by-examples-on-HOW-TO-complete-the-square.lesson>HOW TO complete the square - Learning by examples</A> 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/HOW-TO-solve-quadratic-equation-by-completing-the-square-Learning-by-examples.lesson>HOW TO solve quadratic equation by completing the square - Learning by examples</A> 

in this site.  These lessons were written SPECIALLY FOR YOU.



Also, you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lessons are the part of this textbook under the topic "<U>Quadratic equations</U>". 



Save the link to this online textbook together with its description


Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson


to your archive and use it when it is needed.