The quadratic formula can be derived by completing the square on the standard form quadratic equation ax^2 + bx + c = 0. By completing the square, the equation can be written as (x + b/2a)^2 = (b^2 - 4ac)/4a^2, from which the quadratic formula -b ± √(b^2 - 4ac)/2a can be identified.

1. Glen
George
GG
BS Math III

2. Another way to solve a quadratic equation is to use
the quadratic formula. You can derive this formula
by completing the square as discussed below.
Suppose the given equation is in standard form
ax2 + bx + c = 0
Where a=0. divide both sides of the equation by a.
2
0
b c
x x
a a
  

3. Solve the Equation by completing the square.
2 b c
x x
a a
  
Next, subtract from both sides:
c
a
2 2 2
2
1 b b b
= =
2 a 2a 4a
Now add to both sides:
    
    
    