So we have this problem, right?
x^2-10x+24 (this reads x-square minus 10 plus 24)
So, being good math people, we're know that we first have to figure out the factors of 24 that is going to subtract (or you can think adding) that will give us a negative ten. Well this is the first point that I made. 10 is a negative number, right? And 24 is a positive number, so that means we're are going to have two negative factors, because we know that multiplying two negatives will give us a positive. Well, the only factor that is going to subtract to give us a negative 10 is negative four and negative six, right?
Well, I hope you find this useful and can use this the next time you are factoring.