We can factor the equation x² + 4x - 12 by looking for two numbers that multiply up to -12 and add up to 4x.
Some choices are 12 and -1, 4 and -3 and 6 and -2.
Out of the three, only the difference of 6 and -2 is equal to 4. Notice -6 and 2 would not work because they add up to -4 and not 4 in 4x.
The factored equation's skeleton would be (x- ?)(x+?)
we can plug in the numbers and the answer would be:
(x+6)(x-2)
Check:
factor is out
x²-12x + 6x -12
x²-4x - 12
