Please help I’m stuck!! When do you have to split up the middle
term in a trinomial when factoring?

You typically split up the middle term if your a-value (the coefficient on x^2) is not 1.

For example, I'd split up the middle term on 3x^2 + 4x – 4,

but not on x^2 + 4x - 12.  

Technically you could on that second one, but you're making a lot of extra and unecessary work for yourself.

Does that make sense?

x -

median = 1.25

range = 12-14.5

interquartile = q12-q14.5

y -

median = 1

range = 15-17

interquartile = q15-q17