Evaluate the Function, Set Builder Notation...

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
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Joined: Fri Feb 05, 2010 6:22 pm
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Evaluate the Function, Set Builder Notation...

Greetings,

I'm having some problems, obviously, with some of my math work. There's a few different ones so hopefully this will all make sense...
Any help would be appreciated.

1. Evaluate the function for the given values:
$f(x) = 5 -3x; x = -4, 2$
I'm not sure where to go with that one. I'd assume I'd combine like terms (5+4=9, x+3x=4x), though I'm not sure what to do after that. Nor am I sure what to do with the ", 2".

2. Solve:
$\frac{k+1}{3} - \frac{1}{2} = \frac{3k-3}{6}$
Again, I'm not really sure where to go with this. I've always struggled greatly with fractions...

3. Solve and list the answer in Set Builder Notation:
$4x - 6 > 12 - 10x$
For this one I've got the equation down to...
$6 > -14x$
But I'm not sure what to do from there... (I think I did my combining correctly...?)

And one last question... I've got a problem similar to number 3, however instead of it saying to list the answer in Set Builder Notation it just says to list it graphically. How would I list it graphically? I'm not entirely sure what it's asking me to do.
The problem is almost identical to number 3, just different numbers.

stapel_eliz
Posts: 1628
Joined: Mon Dec 08, 2008 4:22 pm
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1. Evaluate the function for the given values:
$f(x) = 5 -3x; x = -4, 2$
I'm not sure where to go with that one.
They're asking you to plug the given values in for the given variable.

To learn about function notation and how to evaluate functions, try here.
2. Solve:
$\frac{k+1}{3} - \frac{1}{2} = \frac{3k-3}{6}$
Again, I'm not really sure where to go with this.
A good first step in solving this linear equation would probably be to multiply through by the common denominator of 6, as this will eliminate all the fractions.
3. Solve and list the answer in Set Builder Notation:
$4x - 6 > 12 - 10x$
For this one I've got the equation down to...
$6 > -14x$
But I'm not sure what to do from there.
You do almost the same thing as you would have done for "6 = -14x". The only different, when dealing with solving linear inequalities, is that you have to flip the inequality symbol when you multiply or divide through by a negative value.
I've got a problem similar to number 3, however...it just says to list it graphically.
When you study how to solve linear inequalities (in the link for the previous question), you will learn how to show the different formats of answers.