Ok, it's all pretty much like the "$50 coat is on sale for $35".
<span>If the regular price of the coat is $50 and now it is on sale for $35, then it will cost you $15 less, like this: </span>
<span>$50 - $35 = $15 </span>
<span>You could also say the coat was discounted by $15, or the coat was reduced by $15, or you'll save $15 if you buy that coat ($50 - $15 = 35). </span>
<span>You could also put it in terms of percentages. If the discount is $15, you can figure that $15 is what percent of the regular price, like this: </span>
<span>$15 = X% of $50 </span>
<span>$15 = X% x $50 (divide both sides by 50 to isolate X) </span>
<span>15/50 = X% </span>
<span>.30 = X% (multiply by 100 to convert to a non-decimal) </span>
<span>30% = X </span>
<span>So, you can say all of the following and they all mean the same thing: </span>
<span>1. the $50 coat is on sale for $35 </span>
<span>2. the $50 coat is discounted by $15 </span>
<span>3. the $50 coat is reduced by $15 </span>
<span>4. you'll save $15 if you buy this coat </span>
<span>5. the $50 coat is on sale for 30% off </span>
<span>6. the $50 coat is discounted by 30% </span>
<span>7. you'll save 30% if you buy this coat </span>
<span>8. 30% savings! </span>
<span>9. Save 30%! </span>
<span>So, how does that apply to the $18,000 a year? Ok, if Shelby earns $18,000 this year and then earns $19,500 next year, then she gets an additional $1,500 ($19,500 - $18,000 = $1,500). In the coat problem, everything was discounted, on sale, going down. In this problem, everything is going up, increasing. </span>
<span>You know the dollar increase is $1,500. To figure the percent increase, you need to figure out that $1,500 is what % of $18,000. Remember, it's not the $19,500 that was increased; it was an increase on the $18,000: </span>
<span>$1,500 = X% of $18,000 </span>
<span>1,500/18,000 = X% </span>
<span>.083333 = X% </span>
<span>8.3333% = X </span>
<span>One more: If Shelby get a 10% increase in her salary at the end of one year, that's the same as saying that Shelby gets her salary plus she gets 10% more, like this: </span>
<span>$18,000 + (10% of $18,000) = </span>
<span>$18,000 + $1,800 = </span>
<span>$19,800 end of first year </span>
<span>For the second year, her salary begins at $19,800 and increases 10%, like this: </span>
<span>$19,800 + (10% x $19,800) = </span>
<span>$19,800 + $1,980 = </span>
<span>$21,780 end of second year </span>
<span>You can do it from here.</span>
Check the picture below.
so, the hyperbola looks like so, clearly a = 6 from the traverse axis, and the "c" distance from the center to a focus has to be from -3±c, as aforementioned above, the tell-tale is that part, therefore, we can see that c = 2√(10).
because the hyperbola opens vertically, the fraction with the positive sign will be the one with the "y" in it, like you see it in the picture, so without further adieu,
![\bf \begin{cases} h=2\\ k=-3\\ a=6\\ c=2\sqrt{10} \end{cases}\implies \cfrac{[y- (-3)]^2}{ 6^2}-\cfrac{(x- 2)^2}{ b^2}=1 \\\\\\ \cfrac{(y+3)^2}{ 36}-\cfrac{(x- 2)^2}{ b^2}=1 \\\\\\ c^2=a^2+b^2\implies (2\sqrt{10})^2=6^2+b^2\implies 2^2(\sqrt{10})^2=36+b^2 \\\\\\ 4(10)=36+b^2\implies 40=36+b^2\implies 4=b^2 \\\\\\ \sqrt{4}=b\implies 2=b\\\\ -------------------------------\\\\ \cfrac{(y+3)^2}{ 36}-\cfrac{(x- 2)^2}{ 2^2}=1\implies \cfrac{(y+3)^2}{ 36}-\cfrac{(x- 2)^2}{ 4}=1](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Bcases%7D%0Ah%3D2%5C%5C%0Ak%3D-3%5C%5C%0Aa%3D6%5C%5C%0Ac%3D2%5Csqrt%7B10%7D%0A%5Cend%7Bcases%7D%5Cimplies%20%5Ccfrac%7B%5By-%20%28-3%29%5D%5E2%7D%7B%206%5E2%7D-%5Ccfrac%7B%28x-%202%29%5E2%7D%7B%20b%5E2%7D%3D1%0A%5C%5C%5C%5C%5C%5C%0A%5Ccfrac%7B%28y%2B3%29%5E2%7D%7B%2036%7D-%5Ccfrac%7B%28x-%202%29%5E2%7D%7B%20b%5E2%7D%3D1%0A%5C%5C%5C%5C%5C%5C%0Ac%5E2%3Da%5E2%2Bb%5E2%5Cimplies%20%282%5Csqrt%7B10%7D%29%5E2%3D6%5E2%2Bb%5E2%5Cimplies%202%5E2%28%5Csqrt%7B10%7D%29%5E2%3D36%2Bb%5E2%0A%5C%5C%5C%5C%5C%5C%0A4%2810%29%3D36%2Bb%5E2%5Cimplies%2040%3D36%2Bb%5E2%5Cimplies%204%3Db%5E2%0A%5C%5C%5C%5C%5C%5C%0A%5Csqrt%7B4%7D%3Db%5Cimplies%202%3Db%5C%5C%5C%5C%0A-------------------------------%5C%5C%5C%5C%0A%5Ccfrac%7B%28y%2B3%29%5E2%7D%7B%2036%7D-%5Ccfrac%7B%28x-%202%29%5E2%7D%7B%202%5E2%7D%3D1%5Cimplies%20%5Ccfrac%7B%28y%2B3%29%5E2%7D%7B%2036%7D-%5Ccfrac%7B%28x-%202%29%5E2%7D%7B%204%7D%3D1)
