Please factor and tell me how you did it.

3x² + x - 2

Look at leading coefficient: 3
Look at constant term: -2
Factor by finding two integers such that they have a product of leading coefficient times constant and a sum of the coefficient on x.
So factor by finding two nums that multiply to get -6 and add to get 1.
3 and -2, so break down the x in the middle with these two numbers and group factor

3x² + x - 2
= 3x² + 3x - 2x - 2
= 3x(x + 1) - 2(x + 1)
= (3x - 2)(x+1)