Help with math question

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1

<p>Hi all.</p>

<p>I am trying to find how to solve this problem, but every solution that I found just makes it really hard to solve it. Please guide me how to solve it.</p>

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<p>Thank you.</p>

2

<p>I just did this problem a few minutes ago; I don’t know if my method is the best way to solve it but what I did was:</p>

<ol>
<li>Plug in 0 for C and solve for F (F=32) - should be obvious from just looking at the equation. </li>
<li>Add 27 to F (27+32=59). </li>
<li>Solve for C: 59 = (9/5)C + 32 -> C=15</li>
</ol>

<p>Using the solve function on the TI-89 literally takes like 5 seconds, if you don’t want to solve for C by hand and have a TI-89.</p>

3

<p>I would first set F=something and solve for C. I went with F=-40 because I know that’s where the values for C and F overlap so I don’t have to do any math. So when F=-40, C=-40 as well. You can use any value for F to solve it this way, I just went with -40 out of convenience. </p>

<p>Now for the +27 part. What I’m going to do is add 27 to the value I got for F. Then I’m going to solve for C. Then I’m going to find the difference between the +27 value and the original value.</p>

<p>-40+27=-13. Plug in -13 for F and you get:</p>

<p>-13=(9/5)C+32
-45=(9/5)C
C=-25</p>

<p>So when F=-40, C=-40. When F=-13 (-40+27), C=-25.</p>

<p>40-25=15. The value for C increased by 15 degrees. By changing the value for F by 27, it changed the value for C by 15.</p>

<p>The above works too, and it’s probably less confusing</p>

4

<p>I think the easiest way to go about that one is…</p>

<p>Because its not comparing actual temperatures between C and F, just ‘changes’ in temperature (increase/decrease), you can pretty much ignore the 32 value on the end. </p>

<p>To change from C increase/decrease to F inc/dec, you had to multiply by (9/5). </p>

<p>To change from F increase/decrease to C inc/dec, you had to multiply by (5/9). </p>

<p>Because you were given a value in F and need to change it to C, you would multiply the given value in F by (5/9) to change it to an inc/dec in C. </p>

<p>So 27F * (5/9) = 15C. </p>

<p>Hope this helps you out.</p>

5

<p>Here’s another way:</p>

<p>If C=0, then F=32.
Now increase F by 27. So let F=59. We have 59=(9/5)C+32. Subtracting 32 from each side gives 27=(9/5)C. Now multiply each side by 5/9 to get C=15. </p>

<p>So C increases from 0 to 15, and 15 is the answer.</p>

6

<p>Thank you all. </p>

<p>I solved it in a second.</p>