Question 23670
LET THE QUADRATIC BE
 AX^2+BX+C=0...SINCE THIS IS A QUADRATIC ,A IS NOT EQUAL TO ZERO..SO DIVIDING WITH A WE GET 
X^2+BX/A+C/A=0
WRITE IT AS A PERFECT SQUARE USING X^2 AND X TERMS
{X^2+2*X*(B/2A)+(B/2A)^2}-(B/2A)^2+C/A=0
{X+(B/2A)}^2=(B/2A)^2-C/A=B^2/4A^2-C/A=(B^2-4AC)/4A^2
TAKING SQUARE ROOT 
X+B/2A={{{x = ( +- sqrt( B^2-4*A*C ))/(2*A) }}} 
OR
{{{x = (-B +- sqrt( B^2-4*A*C ))/(2*A) }}}