1. ) 1 thru 9 are both natural numbers and whole numbers. 0 is a whole number, but not a natural number.
2.) 6...it is a natural number because it is a counting number and it is whole, it is a whole number and it is an integer as well. It is also rational because it can be turned into a fraction 6/1.
3.) -2 is a rational number because it can be turned into a fraction -2/1, but it is not a whole number because it contains a negative.
4.) That number would be 0
Answer:

Step-by-step explanation:
![\sf \frac{3}{a} x - 4 = 20\\\\Add \ 4 \ to \ both \ sides\\\\\frac{3}{a} x = 20+4\\\\\frac{3}{a} x = 24\\\\Multiply \ both \ sides \ by \ a\\\\3x = 24 * a\\\\Divide \ 3 \ to \ both \ sides\\\\x = 24a / 3\\\\x = 8a\\\\\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Csf%20%5Cfrac%7B3%7D%7Ba%7D%20x%20-%204%20%3D%2020%5C%5C%5C%5CAdd%20%5C%204%20%5C%20to%20%5C%20both%20%5C%20sides%5C%5C%5C%5C%5Cfrac%7B3%7D%7Ba%7D%20x%20%3D%2020%2B4%5C%5C%5C%5C%5Cfrac%7B3%7D%7Ba%7D%20x%20%3D%2024%5C%5C%5C%5CMultiply%20%5C%20both%20%5C%20sides%20%5C%20by%20%5C%20a%5C%5C%5C%5C3x%20%3D%2024%20%2A%20a%5C%5C%5C%5CDivide%20%5C%203%20%5C%20to%20%5C%20both%20%5C%20sides%5C%5C%5C%5Cx%20%3D%2024a%20%2F%203%5C%5C%5C%5Cx%20%3D%208a%5C%5C%5C%5C%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
<h3>~AH1807</h3>
Your answer is option c. The final simplified form should have y to the 4th power instead of y cubed. I think so..