X greater than/equal to 600 and X less than/equal to 2400
To solve the problem:
<span>Let f = distance one way distance on level
ground</span>
<span>
Let h = distance rode on the hill</span>
<span>
Write a time equation; where Time = distance/speed:</span>
<span>
level time + uphill time + downhill time + level time = 1hr</span>
<span>
</span>
<span>f/9 + h/6 + h/18 + f/9 = 1 hr</span>
<span>
Multiply equation by 18 to get rid of the denominators</span>
<span>
</span>
2f + 3h + h + 2f = 18
4f + 4h = 18
Simplify by dividing this by 4
<span>f + h = 4.5 miles is took her to get to Jon’s
house.</span>
They are on opposite sides of zero because one number is negative and one is positive
The answer for the problems are below in the picture let me know if that makes sense.