SOLUTION: I am so very confused. This is from an on line course, Graph the function f(X)=-3^+X-5. At this point I have come up numerous answers

Algebra ->  Rational-functions -> SOLUTION: I am so very confused. This is from an on line course, Graph the function f(X)=-3^+X-5. At this point I have come up numerous answers       Log On


   

Question 129983: I am so very confused. This is from an on line course, Graph the function f(X)=-3^+X-5. At this point I have come up numerous answers
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
I'm assuming you want to graph f%28x%29=-3x%5E2%2Bx-5 right?



In order to graph f%28x%29=-3x%5E2%2Bx-5, we need to plot some points. To do that, we need to plug in some x values to get some y values


So let's find the first point:



f%28x%29=-3x%5E2%2B1x-5 Start with the given function


f%28-1%29=-3%28-1%29%5E2%2B1%28-1%29-5 Plug in x=-1


f%28-1%29=-3%2A1%2B1%2A-1-5 Raise -1 to the 2nd power to get 1


f%28-1%29=-3%2B1%2A-1-5 Multiply -3 and 1 to get -3


f%28-1%29=-3%2B-1-5 Multiply 1 and -1 to get -1


f%28-1%29=-4-5 Add -3 and -1 to get -4


f%28-1%29=-9 Subtract 5 from -4 to get -9


So when x=-1, we have y=-9


So our 1st point is (-1,-9)


-------------- Let's find another point --------------


f%28x%29=-3x%5E2%2B1x-5 Start with the given function


f%280%29=-3%280%29%5E2%2B1%280%29-5 Plug in x=0


f%280%29=-3%2A0%2B1%2A0-5 Raise 0 to the 2nd power to get 0


f%280%29=0%2B1%2A0-5 Multiply -3 and 0 to get 0


f%280%29=0%2B0-5 Multiply 1 and 0 to get 0


f%280%29=0-5 Add 0 and 0 to get 0


f%280%29=-5 Subtract 5 from 0 to get -5


So when x=0, we have y=-5


So our 2nd point is (0,-5)


-------------- Let's find another point --------------


f%28x%29=-3x%5E2%2B1x-5 Start with the given function


f%281%29=-3%281%29%5E2%2B1%281%29-5 Plug in x=1


f%281%29=-3%2A1%2B1%2A1-5 Raise 1 to the 2nd power to get 1


f%281%29=-3%2B1%2A1-5 Multiply -3 and 1 to get -3


f%281%29=-3%2B1-5 Multiply 1 and 1 to get 1


f%281%29=-2-5 Add -3 and 1 to get -2


f%281%29=-7 Subtract 5 from -2 to get -7


So when x=1, we have y=-7


So our 3rd point is (1,-7)


Now lets make a table of the values we have calculated 



 xy



 -1-9
 

 0-5
 

 1-7
Now plot the points



Now connect the points to graph y=-3x%5E2%2B1x-5 (note: the more points you plot, the easier it is to draw the graph)