Answer :
So here we have the trinomial:
[tex]x^2+12x-45[/tex]To factor it, we are going to ask for two numbers, whose sum is 12 and their multiplication is -45.
These numbers are 15 and -3.
Now, we put these numbers into the following brackets:
[tex](x+15)(x-3)[/tex]And that's the factored form.
We obtained 15 and -3 after trying a lot of values. That's an essay on error.
You have to try too many pair of numbers until you get the correct ones.