Answer:
If you mean "How do I write an inequality?", the answer is COEFFICIENTxVARIABLE {any symbol} COEFFICIENTxVARIABLE >/< INTEGER
In other words, you should have something like this: -3x + 4v < 63
Or this: 51x - 16v > 11
Or anything along those lines.
It is 18 because the radius is half the diameter and 9 x 2 = 18.
You have to do 4 times the 8 which is 24. Then find the adding for the -6. 1*6 2*6 3*6 4*6 , 4*6 is 24 so your answer would be (x-4) (x+6)
Place value of 4 is 4/100
2.5 liters = 0.66 gallons