Assuming you want to simplify this expression, you would make use of the distributive property.
... = 3(4u) +3(-2) -2(u) -2(2)
... = 12u -6 -2u -4
... = u(12 -2) +(-6-4)
... = 10u -10
You first use distributive property to solve which is 12u-6-2u-4 then combine like terms which is 10u-10 which is your answer.
