Question 36454
<pre>
Original- ax^2 + bx + c =0 
1. subtract c from each side

ax^2 + bx = -c

2. Divide each side by a

x^2 + (b/a)x = -c/a
3. Add he square of half the coefficient of x to each side

x^2 + (b/a)x + (b/2a)^2 = -c/a + (b/2a)^2

x^2 + (b/a)x + (b^2/4a^2) = -c/a + (b^2/4a^2)

4.write the left side as a perfect square

(x+ b/2a)^2 = -c/a + (b^2/4a^2)

5.use a common denominator to express the right side as a single fraction

(x+ b/2a)^2 = (-4ac + b^2)/(4a^2)

6. find the square root of eac side 

(x+ b/2a)^2 = (b^2 - 4ac)/(4a^2)

(x+ b/2a) = {{{+- sqrt(b^2-4ac)/2a}}}

7. solve for x by subtracting the same term form each side

(x+ b/2a) = {{{+- sqrt(b^2-4ac)/2a}}}

x = {{{ -b/2a (+- sqrt(b^2-4ac)/2a)}}}
8. use a common denominator to express the right side as a single fraction 

x = {{{ ((-b+- sqrt(b^2-4ac))/2a)}}}

</pre>