## Online Course Discussion Forum

### MC III Algebra Help

MC III Algebra Help

Hi,

For 3.21, I calculated the determinant,

$$\Delta = (2(m+1))^2 - 4*1*(3m^2+4mn+4n^2+1) = 2m^2-2m+4mn+4n^2+1 \geq 0$$

I simplified to $$(m-1)^2+(m+2n)^2 \geq 0$$

but I don't know where to go from there since that doesn't tell you anything.

Re: MC III Algebra Help

Are you sure your discriminant is simplified correctly?  You canceled a negative number, and that reverses the direction of the inequality.