Help Please

[katie101]

Determine all the values for k so that the quadratic expression x^2+kx-19 can be factorised using intergers.

I was told to use the discriminent but i can't work it out

[Orb]

Determine all the values for k so that the quadratic expression x^2+kx-19 can be factorised using intergers.

I was told to use the discriminent but i can't work it out

Because you want it factorised using integers only, the only possible solution would be (x-19)(x+1) or (x+19)(x-1) as 19 is a prime number and a=1.

So it's either x^2+18x-19 or x^2-18x-19. So k= 18 or -18

I'm not sure that the discriminant is necessary nor useable as it's used to determine the number of solutions for the equation.