ANSWER
Mel followed the right direction.
EXPLANATION
Pat's trinomial is;
[tex] {x}^{2} + 3x - 10[/tex]
There are factors of -10 that sums up to 3.
[tex]5 + - 2 = 3[/tex]
Hence this trinomial could be factored into (x-2)(x+5)
Sam's trinomial:
[tex] {x}^{2} + x - 12[/tex]
There are factors of -12 that sums up to 1.
4+-3=1
[tex] {x}^{2} + x - 12 = (x + 4)(x - 3)[/tex]
Mel's trinomial:
[tex] {x}^{2} + 2x - 1[/tex]
There are no factors of -1 that sums to 2.
This trinomial cannot be factored.
Lee's trinomial:
[tex] {x}^{2} + 2x - 3[/tex]
There are factors of -3 that sums up to 2
3+-1=2
[tex] {x}^{2} + 2x + 3 = (x + 3)(x - 1)[/tex]