It is important because if you are adding and subtracfing and the decimals are off when your done with the equation you might end up with two decimals or numbers in the wrong place
Answer:
7a + 14
just multiply 7 by both a and 2
I=PRT
P=8000
R=0.015
T=3
I=8000*0.015*3=360
total amount=8000+360=$8360
the answer is 5 if you need an explanation ask for it in the comments