The discriminant tells us there are two roots when positive, one root when zero, and no roots when negative. #b^2-4ac = (-8)^2-4*3*1 = 52# is positive, so there are two roots. The discriminant is just part of the quadratic equation. The quadratic equation gives us the exact real number roots of any equation in the form #ax^2+bx+c=0#. The quadratic equation is #x = (-b \pm sqrt(b^2-4ac))/(2a)#, where #\pm# means that we have two values, one using #+# (addition) and one using #-# (subtraction).
Head Lice vs. Dandruff: How to Tell the Difference. Head lice and dandruff are two completely different things, yet people often mistake one for the other. Head lice are parasites that feed on human blood, and are spread through contact with others. Their bites cause an itchy scalp and occasionally an allergic reaction. Dandruff is a skin condition on the scalp that causes flaking of the skin and a slightly itchy scalp. Here's how to tell the difference between the two. Head lice are small, brown parasites with six legs about the size of a sesame seed. They have elongated bodies, with small, oval shaped heads.
Lice. Lice are small, grayish-brown insects that live on humans. Lice bite through the skin and live on the blood of the host, another name for the infected person. Female lice lay eggs -- called nits -- that firmly attach to hair shafts. Head lice live on the scalp and are common among school children.Lice also can be found on the body (body lice) or in the pubic region (pubic lice). Head lice are spread by direct head to head contact and by sharing items including combs, brushes, scarves, and hats with an infected person.Pubic lice (crabs) are spread by having close physical contact with someone who has them.ice. Lice are small, grayish-brown insects that live on humans. Lice bite through the skin and live on the blood of the host, another name for the infected person. Female lice lay eggs -- called nits -- that firmly attach to hair shafts. Head lice live on the scalp and are common among school children.