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anonymous
 one year ago
Can you help me understand how to do this problem. Given the function f(x) = 4(x+3)  5, solve for the inverse function when x = 3. (1 point)
anonymous
 one year ago
Can you help me understand how to do this problem. Given the function f(x) = 4(x+3)  5, solve for the inverse function when x = 3. (1 point)

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0To make this easier, let y = f(x). So, we have: \[y = 4(x + 3)  5\]To solve for the inverse, switch x and y. \[x = 4(y + 3)  5\]Now, solve for y again in terms for x. Can you take it from there?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.03=4y+12  5 so 3=4y+7 so 4=4y so y=1?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Yes! Good job! Also, there's a cool little trick to inverse functions like this. If you're trying to find what the inverse is at an xvalue, you can just plug that in for y (or f(x)) in the original and solve for x.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Can you give me an example? Im not sure I understand that.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0what about this when you don't have a value for x and need to do the inverse? Given the function f(x) = 5x3/4 , which of the below expressions is correct? f1(x) = 35x/4 f1(x) = 4x+3/5 f1(x) = 4x3/5 f1(x) = 5x3/4

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Follow the same steps as in the first example, but this time, since you don't have any values to plug in, leave the x there and solve for y in terms of x. Then, once you get y by itself, replace it with \(f^{1}(x)\).

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0So, to get you started, \[f(x) = 5x\frac34\]\[y=5x\frac34\]\[x=5y\frac34\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0it's actually 5x3 over 4

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0it wouldn't copy the equation correctly.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Ah ok. No problem. \[f(x) = \frac{5x3}{4}\]\[y=\frac{5x3}{4}\]\[x=\frac{5y3}{4}\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0then how do i do the f1(x)

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2split the fractions up \[x = \frac{5y}{4} \frac{3}{4}\]

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2now add 3/4 to both sides.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Well, remember when we let y = f(x)? Solve for y first, then you can just replace the y with the \(f^{1}(x)\). It's just a notation thing. You can work with f(x) the entire time, it's just a bit messy.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Do you need help with the algebra to solve for y or can you do that part?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0can you help? I got y=3+4X? Is that right?

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2let me check that for a sec

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Not quite. I think you forgot the 5 somewhere.

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2\[x + \frac{3}{4}= \frac{5y}{4}\] then divide 5/4 throughout the entire equation .

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0\[x = \frac{5y  3}{4}\]\[4x = 5y  3\]\[5y = 4x + 3\]It looks like you got to here in your algebra. All that's left to do is divide by 5 to get y by itself. Do you get it?

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2dw:1439784708621:dwdw:1439784747500:dw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I multiplied the entire equation by 4 in the first step, then added 3 on both sides in those first two steps.

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2dw:1439784792258:dw it was a good attempt. just that the 5 was missing ^_^

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Remember, you're basically doing the opposite of PEMDAS to solve for a variable. Just work backwards!

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2now the last step is to replace that y with \[f^{1}(x )\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Yes ^. Like I said before, we let y = f(x) to make it more convenient when writing (It'd take a while to write f(x) and f^1(x) every time!). So now, you can just replace y with \(f^{1}(x)\). You can decide to solve it using the f(x), and it'd still be correct, it'd just take longer to write and is a bit more confusing if you're new to algebra. :)

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2dw:1439785031869:dw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Do you know how to explain how to do this? On the graph of the equation 3x + 2y = 18, what is the value of the yintercept?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I'm going to sleep in a few minutes, but this last one, sure. A yintercept is basically where the graph touches the yaxis. What do we know about the xvalue at the yaxis?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0That's the only information it gives me

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0and these are the answer choices 9 6 6 9

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2for this equation 3x+2y=18 we need this in y = mx+b form where m is the slope and b i s the y intercept. You need to rearrange this equation and divide the whole equation by 2

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I know, I'm trying to get you through the question without my outright giving you how to do it.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@UsukiDoll I personally think there's a much easier way to do this question, but that works too.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ah okay. Well i put it in y=mx+b format, then I wasn't sure what to do

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0If you did put it into y = mx + b, then b is your yintercept by definition.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0So the answer would be 9

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Yes, it is 9. The point I was trying to make earlier is this. You learned in algebra that the yintercept is where the graph hits the yaxis, correct?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Yes that makes sense! Thank you for your help! I appreciate it!

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.22y=3x+18 y = 3/2x+9 3/2 < slope 9<yintercept.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0At the yaxis, the xvalue of all points on the yaxis is 0. In other words, the yintercept is when x = 0. So, another way to do it (personally faster) is to just let x = 0 and solve for y. \[3x + 2y = 18\]\[3(0) + 2y = 18\]\[2y = 18\]\[y = 9\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0However, either way works, of course. :)

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2oh .. that's what you mean by easier way. I never thought of that when I used to to do these problems. for yintercept, set x = 0 and solve for y XD

UsukiDoll
 one year ago
Best ResponseYou've already chosen the best response.2I was taught to rearrange to y = mx+b and if there's a number next to y, divide the whole equation by that number. wow tsk tsk. the math professors keeping their good secrets lol

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0y=mx+b is how I learned, but that makes sense.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0lol yeah, lots of ways to think about these types of problems. It's just in the beginning, it's hard to grasp the concept, so you learn rules and directions like (just put into y = mx + b first). However, as you get more used to it, you can start to think about it more and you get little tricks like that.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Anyway, I'm going to sleep. I'm sure if you have anymore questions, others will be glad to help you @gmanmoney .

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Brittany was tracking the increasing temperature in the morning. At 8 a.m. it was 68 degrees Fahrenheit. At 10 a.m. it was 74 degrees Fahrenheit. If Brittany made the function f(x) = 3x + 36, what would the 36 represent? (1 point) The temperature at midnight The rate the temperature was increasing The length of time she recorded for The total change in degrees

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0How would I do this one?
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