Answer:19+3x
Step-by-step explanation:I got my answer by first distributing the 3 so my equation should then look like this 4+(15+3x). Then I group the 4 and the 15 because you cannot add 3x by 15. So your problem should then look like this (4+15)+3x. Finally you add 15 and 4 and get 19. Then you drop it down next to the +3x so my problem should now look like this 19+3x. This is not only an equivalent expression but it is also the simplified version
