Answer:
y = a(x +b/(2a))^2 + (4ac -b^2)/(4a)
Step-by-step explanation:
We presume you're starting with ...
y = ax^2 +bx +c
As you would with numbers, factor the first two terms:
y = a(x^2 +b/a·x) +c
Add half the square of the x term inside and its opposite outside parentheses:
y = a(x^2 +(b/a)x + (b/(2a))^2) + c - a(b/(2a))^2
y = a(x +b/(2a))^2 +c -b^2/(4a)
You can combine the last two terms to a more familiar fraction:
y = a(x +b/(2a))^2 + (4ac -b^2)/(4a)
