For x you insert zero, and
0 = 2 - 8 * 0
0 = 2
Answer: 
Step-by-step explanation:
You need to used the following formula:

Where "V" is the speed, "d" is the distance and "t" is the time.
In this case you know that Kevin traveled at a constant speed on the highway from Hickory Hills to Chicago in 20 minutes (which is
) and the distance is 17 miles. Then, you can identify that:

Therefore, knowing these values, you can substitute them into the formula. Then, you get:
Answer:
80
Step-by-step explanation:
The trick is to pick something that should be very easy to get an answer to. If you use a calculator, you are not estimating. 80 divide by 4 is like 8 divide by 4 which gives you 2. Then just add a zero. Here's another one you can try. Put your calculator away to do it. 12 chicken noodle soup cans cost 14 dollars. About how much does 1 can cost
no cheating. No calculator. Is the cost of 1 can more or less than a dollar? If you said more, you've estimated correctly.
Try it the other way. Suppose one can of the soup costs 0.95 cents. How many will 12 cans cost? More or less than 12 dollars.
If you said less, you are estimating correctly. The most useful gift you can take away from any math class is estimation.