Find and Simplify
- Thread starter Steve101
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Please show us what you have tried and exactly where you are stuck.
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Please share your work/thoughts about this problem.
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No idea... I dont know where to begin for these problems. I suck at math bad.
Dr.Peterson
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You haven't shown your work, which would let us know what you are doing wrong; so I'll assume that you just don't know what to do at all.
Here is a similar problem: Given that \(h(x) = 2x^2 + 3x - 2\), what is \(2h(3t)-4\)?
We can first find what \(h(3t)\) is. That means replacing x in the formula with 3t: \(h(3t) = 2(3t)^2 + 3(3t) - 2 = 2(9t^2)+9t-2 = 18t^2 + 9t - 2\). Do you understand that part?
Now, \(2h(3t)-3\) means we take what we just found, multiply it by 2, and subtract 3: \(2h(3t)-3 = 2[18t^2 + 9t - 2]-3 = 36t^2 + 18t - 4 - 3 = 36t^2 + 18t - 7\).
Now, try your problems, each of which is easier than this one. Then we can see if there's more we need to do for you.
By the way, another way to show what help you need would be to show us the work on the last problem that you were able to do, since you've implied that there were some.
Steven G
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Dr Peterson showed you his way and it was excellent.
Here is my way. Instead of writing x as x, I write x as ( ). That is, wherever I see x, I write ( ). OK
We have f(x) = 4x2 + 4x - 3. So what I write is f( ) = 4( )2 + 4( ) - 3.
Now if they want me to find f(a), I go back to my last line and place a in all the parenthesis.
We have f( ) = 4( )2 + 4( ) -3 and it becomes f(a) = 4(a)2 + 4(a) -3.
Note that I did NO mathematics at all. I like to call it art work. All I did was replace all x's with ( )'s and then I put in between all the ( ) exactly what the problem had between the ( ), namely a.
Now the math starts. You need to simplify 4(a)2 + 4(a) -3 and multiply this result by 2.
In my opinion, what students find the hardest, finding f(something), is the easiest part if you do it in a way that you understand.
In this thread you have been giving two ways to do the start of problems like this. Either do it one of these two ways or figure out your own technique. If you do not understand how your teacher does it, that is fine. However that does not mean that you can't go ahead and figure out your own method/style.
Post back with your work.
Here is my way. Instead of writing x as x, I write x as ( ). That is, wherever I see x, I write ( ). OK
We have f(x) = 4x2 + 4x - 3. So what I write is f( ) = 4( )2 + 4( ) - 3.
Now if they want me to find f(a), I go back to my last line and place a in all the parenthesis.
We have f( ) = 4( )2 + 4( ) -3 and it becomes f(a) = 4(a)2 + 4(a) -3.
Note that I did NO mathematics at all. I like to call it art work. All I did was replace all x's with ( )'s and then I put in between all the ( ) exactly what the problem had between the ( ), namely a.
Now the math starts. You need to simplify 4(a)2 + 4(a) -3 and multiply this result by 2.
In my opinion, what students find the hardest, finding f(something), is the easiest part if you do it in a way that you understand.
In this thread you have been giving two ways to do the start of problems like this. Either do it one of these two ways or figure out your own technique. If you do not understand how your teacher does it, that is fine. However that does not mean that you can't go ahead and figure out your own method/style.
Post back with your work.
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