b^2-4ac. what does this mean and where do u use it..?

Question

ASAP

Answer 1

this is called the discriminant
if its < 0 then the quadratic will never cut the x-axis (Imaginary roots)
If its = 0
then roots are real and equal
if its > 0
then roots are real and distinct

Answer 2

b^2-4ac is used for the resolution of the equation
ax^2+bx+c=0

3cases 1) b^2-4ac>0 then you have two solutions for the roots x1= (-b + (b^2-4ac)^0.5)/2a and
x2 = (-b -(b^2-4ac)^0.5)/2a

2) b^2-4ac=0 one root x = -b/2a

3) b^2-4ac<0 no real roots (complex )

Answer 3

it is known as the discriminator D
if D>0 equation(eqn) will have positive and real roots and if
D==0 then the quad eqn will have equal roots and if u have D<0 then the quad eqn will have complex roots.