SOLUTION: How do you put 2n^2-4n-6=0 in to a graph or table . Round to the nearst tenth

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Question 117549: How do you put 2n^2-4n-6=0 in to a graph or table . Round to the nearst tenth
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
In order to make a table, just plug in some n values. So I'm going to start at n=-5


Let's evaluate f%28-5%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%28-5%29=2%28-5%29%5E2-4%28-5%29-6 Plug in n=-5. In other words, replace each n with -5.


f%28-5%29=2%2825%29-4%28-5%29-6 Evaluate %28-5%29%5E2 to get 25.


f%28-5%29=%2B50-4%28-5%29-6 Multiply 2 and 25 to get 50


f%28-5%29=%2B50%2B20-6 Multiply -4 and -5 to get 20


f%28-5%29=64 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%28-4%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%28-4%29=2%28-4%29%5E2-4%28-4%29-6 Plug in n=-4. In other words, replace each n with -4.


f%28-4%29=2%2816%29-4%28-4%29-6 Evaluate %28-4%29%5E2 to get 16.


f%28-4%29=%2B32-4%28-4%29-6 Multiply 2 and 16 to get 32


f%28-4%29=%2B32%2B16-6 Multiply -4 and -4 to get 16


f%28-4%29=42 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%28-3%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%28-3%29=2%28-3%29%5E2-4%28-3%29-6 Plug in n=-3. In other words, replace each n with -3.


f%28-3%29=2%289%29-4%28-3%29-6 Evaluate %28-3%29%5E2 to get 9.


f%28-3%29=%2B18-4%28-3%29-6 Multiply 2 and 9 to get 18


f%28-3%29=%2B18%2B12-6 Multiply -4 and -3 to get 12


f%28-3%29=24 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%28-2%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%28-2%29=2%28-2%29%5E2-4%28-2%29-6 Plug in n=-2. In other words, replace each n with -2.


f%28-2%29=2%284%29-4%28-2%29-6 Evaluate %28-2%29%5E2 to get 4.


f%28-2%29=%2B8-4%28-2%29-6 Multiply 2 and 4 to get 8


f%28-2%29=%2B8%2B8-6 Multiply -4 and -2 to get 8


f%28-2%29=10 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%28-1%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%28-1%29=2%28-1%29%5E2-4%28-1%29-6 Plug in n=-1. In other words, replace each n with -1.


f%28-1%29=2%281%29-4%28-1%29-6 Evaluate %28-1%29%5E2 to get 1.


f%28-1%29=%2B2-4%28-1%29-6 Multiply 2 and 1 to get 2


f%28-1%29=%2B2%2B4-6 Multiply -4 and -1 to get 4


f%28-1%29=0 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%280%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%280%29=2%280%29%5E2-4%280%29-6 Plug in n=0. In other words, replace each n with 0.


f%280%29=2%280%29-4%280%29-6 Evaluate %280%29%5E2 to get 0.


f%280%29=%2B0-4%280%29-6 Multiply 2 and 0 to get 0


f%280%29=%2B0%2B0-6 Multiply -4 and 0 to get 0


f%280%29=-6 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%281%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%281%29=2%281%29%5E2-4%281%29-6 Plug in n=1. In other words, replace each n with 1.


f%281%29=2%281%29-4%281%29-6 Evaluate %281%29%5E2 to get 1.


f%281%29=%2B2-4%281%29-6 Multiply 2 and 1 to get 2


f%281%29=%2B2-4-6 Multiply -4 and 1 to get -4


f%281%29=-8 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%282%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%282%29=2%282%29%5E2-4%282%29-6 Plug in n=2. In other words, replace each n with 2.


f%282%29=2%284%29-4%282%29-6 Evaluate %282%29%5E2 to get 4.


f%282%29=%2B8-4%282%29-6 Multiply 2 and 4 to get 8


f%282%29=%2B8-8-6 Multiply -4 and 2 to get -8


f%282%29=-6 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%283%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%283%29=2%283%29%5E2-4%283%29-6 Plug in n=3. In other words, replace each n with 3.


f%283%29=2%289%29-4%283%29-6 Evaluate %283%29%5E2 to get 9.


f%283%29=%2B18-4%283%29-6 Multiply 2 and 9 to get 18


f%283%29=%2B18-12-6 Multiply -4 and 3 to get -12


f%283%29=0 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%284%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%284%29=2%284%29%5E2-4%284%29-6 Plug in n=4. In other words, replace each n with 4.


f%284%29=2%2816%29-4%284%29-6 Evaluate %284%29%5E2 to get 16.


f%284%29=%2B32-4%284%29-6 Multiply 2 and 16 to get 32


f%284%29=%2B32-16-6 Multiply -4 and 4 to get -16


f%284%29=10 Now combine like terms


-----------Now let's evaluate another value---------


Let's evaluate f%285%29


f%28x%29=2n%5E2-4n-6 Start with the given function.


f%285%29=2%285%29%5E2-4%285%29-6 Plug in n=5. In other words, replace each n with 5.


f%285%29=2%2825%29-4%285%29-6 Evaluate %285%29%5E2 to get 25.


f%285%29=%2B50-4%285%29-6 Multiply 2 and 25 to get 50


f%285%29=%2B50-20-6 Multiply -4 and 5 to get -20


f%285%29=24 Now combine like terms




Now lets make a table of the values we have calculated 



 xy



 -564
 

 -442
 

 -324
 

 -210
 

 -10
 

 0-6
 

 1-8
 

 2-6
 

 30
 

 410
 

 524
Now plot the points



Now connect the points to graph y=2n%5E2-4n-6 (just replace n with x) (note: the more points you plot, the easier it is to draw the graph)