Question

For the equation x2 + 3x + j = 0, find all the values of j such that the equation has two real number solutions.

Answer 1

Do you know what the discriminant is? It must be 0 or positive for pure real roots.

Answer 2

thats all they gave me for the problem

Answer 3

Here are the gory details
http://en.wikipedia.org/wiki/Quadratic_equation#Quadratic_formula

Answer 4

I don't get how to work this out

Answer 5

do you by chance have any advice on how to work it out?

Answer 6

You match your equation to the form
\[a x^2 +bx+c =0\]
\[ x^2 + 3x + j = 0 \]
so what is a? b? c?

once you know a,b,c, you use them in
\[ b^2 -4ac ≥ 0\]

Answer 7

For example, in
\[ x^2 +3x +j=0 \] a must be 1