SOLUTION: Can you please help me graph this equation? y=-x^2+6x+5

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Question 128757: Can you please help me graph this equation?
y=-x^2+6x+5

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
In order to graph , 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:



Start with the given function


Plug in


Raise -2 to the 2nd power to get 4


Multiply -1 and 4 to get -4


Multiply 6 and -2 to get -12


Add -4 and -12 to get -16


Add -16 and 5 to get -11


So when , we have


So our 1st point is (-2,-11)


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


Start with the given function


Plug in


Raise -1 to the 2nd power to get 1


Multiply -1 and 1 to get -1


Multiply 6 and -1 to get -6


Add -1 and -6 to get -7


Add -7 and 5 to get -2


So when , we have


So our 2nd point is (-1,-2)


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


Start with the given function


Plug in


Raise 0 to the 2nd power to get 0


Multiply -1 and 0 to get 0


Multiply 6 and 0 to get 0


Add 0 and 0 to get 0


Add 0 and 5 to get 5


So when , we have


So our 3rd point is (0,5)


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


Start with the given function


Plug in


Raise 1 to the 2nd power to get 1


Multiply -1 and 1 to get -1


Multiply 6 and 1 to get 6


Add -1 and 6 to get 5


Add 5 and 5 to get 10


So when , we have


So our 4th point is (1,10)


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


Start with the given function


Plug in


Raise 2 to the 2nd power to get 4


Multiply -1 and 4 to get -4


Multiply 6 and 2 to get 12


Add -4 and 12 to get 8


Add 8 and 5 to get 13


So when , we have


So our 5th point is (2,13)


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


Start with the given function


Plug in


Raise 3 to the 2nd power to get 9


Multiply -1 and 9 to get -9


Multiply 6 and 3 to get 18


Add -9 and 18 to get 9


Add 9 and 5 to get 14


So when , we have


So our 6th point is (3,14)


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


Start with the given function


Plug in


Raise 4 to the 2nd power to get 16


Multiply -1 and 16 to get -16


Multiply 6 and 4 to get 24


Add -16 and 24 to get 8


Add 8 and 5 to get 13


So when , we have


So our 7th point is (4,13)


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


Start with the given function


Plug in


Raise 5 to the 2nd power to get 25


Multiply -1 and 25 to get -25


Multiply 6 and 5 to get 30


Add -25 and 30 to get 5


Add 5 and 5 to get 10


So when , we have


So our 8th point is (5,10)


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


Start with the given function


Plug in


Raise 6 to the 2nd power to get 36


Multiply -1 and 36 to get -36


Multiply 6 and 6 to get 36


Add -36 and 36 to get 0


Add 0 and 5 to get 5


So when , we have


So our 9th point is (6,5)


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


Start with the given function


Plug in


Raise 7 to the 2nd power to get 49


Multiply -1 and 49 to get -49


Multiply 6 and 7 to get 42


Add -49 and 42 to get -7


Add -7 and 5 to get -2


So when , we have


So our 10th point is (7,-2)


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


Start with the given function


Plug in


Raise 8 to the 2nd power to get 64


Multiply -1 and 64 to get -64


Multiply 6 and 8 to get 48


Add -64 and 48 to get -16


Add -16 and 5 to get -11


So when , we have


So our 11th point is (8,-11)


Now lets make a table of the values we have calculated
xy
-2-11
-1-2
05
110
213
314
413
510
65
7-2
8-11
Now plot the points



Now connect the points to graph (note: the more points you plot, the easier it is to draw the graph)

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