y=ax*2+bx+c
y=a(x*2+b/a•x)+c
y=a[x*2+b/a•x+(b/(2a))*2-(b/(2a))*2]+c
y=a[(x+b/(2a))*2-(b/(2a))*2]+c
y=a(x+b/(2a))*2-a•b*2/(4a*2)+c
y=a(x+b/(2a))*2-b*2/(4a)+4ac/(4a)
y=a[x+b/(2a)]*2+(4ac-b*2)/(4a)
y=ax*2+bx+c
y=a(x*2+b/a•x)+c
y=a[x*2+b/a•x+(b/(2a))*2-(b/(2a))*2]+c
y=a[(x+b/(2a))*2-(b/(2a))*2]+c
y=a(x+b/(2a))*2-a•b*2/(4a*2)+c
y=a(x+b/(2a))*2-b*2/(4a)+4ac/(4a)
y=a[x+b/(2a)]*2+(4ac-b*2)/(4a)