If x - 3 is a factor of x2 + x - 12, then the other factor is

x + 4

Step-by-step explanation:

You have to factor x2 + x - 12 using sum product number pair or the box method.

spnp would be

s p n p

1 - 12 - 3, 4

Therefore the factored form would be:

(x - 3) (x + 4)

making the other factor

x + 4