Which expression is equivalent to 14j - 7j+9+ 4k +6

How do i do this activity, is appreciated

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)

Me. i can't figure out this question. give an explanation too. .