The 6 hour time frame is extraneous information, do not worry about it!
h≥4.5
Practice makes perfect
If the temperature is decreasing by 8^(∘)F each hour h, we can express the change in temperature algebraically as -8h. We want to know when the temperature has dropped by at least 36^(∘)F. The other side of an inequality would then be -36.
-8h ... -36
To decide the direction of the inequality sign, let's look at a number line.
We want to know when the drop in temperature is greater than 36. This means that we need to go more negative which, in an inequality and on a number line, means we need to be less than -36. So our inequality becomes the following.
-8h≤ -36
We can solve this for h.
