SOLUTION: Another graphing a function question! I can't figure the graphing part out. Graph the function f(x)= -3x squared + x-5

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Question 152928: Another graphing a function question! I can't figure the graphing part out.
Graph the function f(x)= -3x squared + x-5
Found 2 solutions by jim_thompson5910, Fombitz:
Answer by jim_thompson5910(21685) About Me  (Show Source):
You can put this solution on YOUR website!

Table of Contents:


Jump to Table
Jump to Graph


In order to graph y=-3x%5E2%2Bx-5, we need to plot some points.


Let's find y when x=-2
(Note: you can start with any x-value):


y=-3x%5E2%2Bx-5 Start with the given equation.


y=-3%28-2%29%5E2%2B-2-5 Plug in x=-2.


y=-3%284%29-2-5 Square -2 to get 4.


y=-12-2-5 Multiply -3 and 4 to get -12.


y=-19 Combine like terms.


So when x=-2, then y=-19.


So we have the point .


----------------------------------------------------


Let's find y when x=-1:


y=-3x%5E2%2Bx-5 Start with the given equation.


y=-3%28-1%29%5E2%2B-1-5 Plug in x=-1.


y=-3%281%29-1-5 Square -1 to get 1.


y=-3-1-5 Multiply -3 and 1 to get -3.


y=-9 Combine like terms.


So when x=-1, then y=-9.


So we have the point .


----------------------------------------------------


Let's find y when x=0:


y=-3x%5E2%2Bx-5 Start with the given equation.


y=-3%280%29%5E2%2B0-5 Plug in x=0.


y=-3%280%29%2B0-5 Square 0 to get 0.


y=0%2B0-5 Multiply -3 and 0 to get 0.


y=-5 Combine like terms.


So when x=0, then y=-5.


So we have the point .


----------------------------------------------------


Let's find y when x=1:


y=-3x%5E2%2Bx-5 Start with the given equation.


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


y=-3%281%29%2B1-5 Square 1 to get 1.


y=-3%2B1-5 Multiply -3 and 1 to get -3.


y=-7 Combine like terms.


So when x=1, then y=-7.


So we have the point .


----------------------------------------------------


Let's find y when x=2:


y=-3x%5E2%2Bx-5 Start with the given equation.


y=-3%282%29%5E2%2B2-5 Plug in x=2.


y=-3%284%29%2B2-5 Square 2 to get 4.


y=-12%2B2-5 Multiply -3 and 4 to get -12.


y=-15 Combine like terms.


So when x=2, then y=-15.


So we have the point .


----------------------------------------------------





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Now let's make a table of the values we just found.


Table of Values:





xy
-2-19


-1-9


0-5


1-7


2-15

Now let's plot the points:


+drawing%28900%2C+900%2C+-10%2C+10%2C+-21%2C+2%2C%0D%0Agrid%281%29%2C%0D%0Agraph%28900%2C+900%2C+-10%2C+10%2C+-21%2C+2%2C+0%29%2C%0D%0Acircle%28-2%2C-19%2C0.08%29%2Ccircle%28-2%2C-19%2C0.10%29%2C%0D%0Acircle%28-1%2C-9%2C0.08%29%2Ccircle%28-1%2C-9%2C0.10%29%2C%0D%0Acircle%280%2C-5%2C0.08%29%2Ccircle%280%2C-5%2C0.10%29%2C%0D%0Acircle%281%2C-7%2C0.08%29%2Ccircle%281%2C-7%2C0.10%29%2C%0D%0Acircle%282%2C-15%2C0.08%29%2Ccircle%282%2C-15%2C0.10%29%0D%0A%0D%0A%29




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Graph:


Now draw a curve through all of the points to graph y=-3x%5E2%2Bx-5:


+drawing%28900%2C+900%2C+-10%2C+10%2C+-21%2C+2%2C%0D%0Agrid%281%29%2C%0D%0Agraph%28900%2C+900%2C+-10%2C+10%2C+-21%2C+2%2C+-3x%5E2%2Bx-5%29%2C%0D%0Acircle%28-2%2C-19%2C0.08%29%2Ccircle%28-2%2C-19%2C0.10%29%2C%0D%0Acircle%28-1%2C-9%2C0.08%29%2Ccircle%28-1%2C-9%2C0.10%29%2C%0D%0Acircle%280%2C-5%2C0.08%29%2Ccircle%280%2C-5%2C0.10%29%2C%0D%0Acircle%281%2C-7%2C0.08%29%2Ccircle%281%2C-7%2C0.10%29%2C%0D%0Acircle%282%2C-15%2C0.08%29%2Ccircle%282%2C-15%2C0.10%29%0D%0A%0D%0A%29 Graph of y=-3x%5E2%2Bx-5

Answer by Fombitz(13823) About Me  (Show Source):
You can put this solution on YOUR website!
Make a table labels x and f(x) or y.
Choose an x. Plug it into the equation, that's your f(x) or y value.
Each x will have a y value.
Graph the points.
Connect the points.
I'll start at x=-5 and go in steps of 1 to x=5.
x,f(x)
-5,-85
-4,-57
-3,-35
-2,-19
-1,-9
0,-5
1,-7
2,-15
3,-29
4,-49
5,-75
.
.
.
Graph the points.
drawing%28+300%2C+300%2C+-5%2C+5%2C+-100%2C+100%2Cgrid%28+1+%29%2C%0D%0Acircle%28-5%2C-85%2C.1%29%2C%0D%0Acircle%28-4%2C-57%2C.1%29%2C%0D%0Acircle%28-3%2C-35%2C.1%29%2C%0D%0Acircle%28-2%2C-19%2C.1%29%2C%0D%0Acircle%28-1%2C-9%2C.1%29%2C%0D%0Acircle%280%2C-5%2C.1%29%2C%0D%0Acircle%281%2C-7%2C.1%29%2C%0D%0Acircle%282%2C-15%2C.1%29%2C%0D%0Acircle%283%2C-29%2C.1%29%2C%0D%0Acircle%284%2C-49%2C.1%29%2C%0D%0Acircle%285%2C-75%2C.1%29%29+
.
.
.
Connect the points.
drawing%28+300%2C+300%2C+-5%2C+5%2C+-100%2C+100%2Cgrid%28+1+%29%2C%0D%0Acircle%28-5%2C-85%2C.1%29%2C%0D%0Acircle%28-4%2C-57%2C.1%29%2C%0D%0Acircle%28-3%2C-35%2C.1%29%2C%0D%0Acircle%28-2%2C-19%2C.1%29%2C%0D%0Acircle%28-1%2C-9%2C.1%29%2C%0D%0Acircle%280%2C-5%2C.1%29%2C%0D%0Acircle%281%2C-7%2C.1%29%2C%0D%0Acircle%282%2C-15%2C.1%29%2C%0D%0Acircle%283%2C-29%2C.1%29%2C%0D%0Acircle%284%2C-49%2C.1%29%2C%0D%0Acircle%285%2C-75%2C.1%29%2C%0D%0Agraph%28+300%2C+300%2C+-5%2C+5%2C+-100%2C+100%2C+-3x%5E2%2Bx-5%29%29+