How to complete the square to solve quadratic equations?
Equation: x2 +4x-5=0 (This is in the form ax2+2bx+c=0)First divide 2b by 2 (4/2=2)Then put this into (x+b)2-(b)2+c=0This gives: (x+2)2-(2)2+ -5=0 (remembering +and- makes a -)Simplify to: (x+2)2-9=0Move the 9 across: (x+2)2=9Square root both sides: x+2=+-3 (remembering the plus and minus roots)Then take away 2 from both sides to give: x= -2+-3And the two values for x now are 1 and -5
