Hey! i’ll give brainliest please help!

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under

Ivan and jeff buy a package of 8 pens for $4.00. ivan wants 5 of the pens, and jeff wants 3.how much should each student pay?

If f(x) =3x-2 and g(x) =2x+1 fins (f+ g) (x)