Answer:
a=1, b=2, c=5, d=1, e=6
Step-by-step explanation:
So 
5ab * (-a) + 5ab * (-5b) + 5ab * 3
X=7 because 7+6=13 and 3•13=39
I would go with either NIST or SIKG. I put SIKG because the abbreviation for mass is kg and you r look for the SI unit of mass and then the SI stands for International System of units. So when you put both SI And KG (kilograms=mass) it makes SIKG.
This is probably not right but I tried.
Good Luck!
It is 2/3 because 16 divided by 8 is 2 and 24 divided by 8 is 3
