SOLUTION: i want to know how to graph y=-x^2+16x , bt i want to know how todo the t-table .

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Question 243661: i want to know how to graph y=-x^2+16x , bt i want to know how todo the t-table .
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
y=-x%5E2%2B16x

Start with this t-table:

 x | y
-------
   | 0
   |
   |

First find the x-intercepts by substituting 0 for y

0=-x%5E2%2B16x

x%5E2-16x=0

x%28x-16%29=0

x=0

x-16=0
x=16

This give us two points with y=0

 x | y
-------
 0 | 0
16 | 0
   |

Now choose a value of x halfway between
the two x-intercepts:

 x | y
-------
 0 | 0
16 | 0
 8 |

y=-x%5E2%2B16x
y=-%288%29%5E2%2B16%288%29
y=-64%2B128
y=64

So we have this t-table:

 x |  y
--------
 0 |  0
16 |  0
 8 | 64

Use a large scale to accommodate those points.
It is not necessary to mark off the x-axis and 
y-axis with the same scale.

Plot those three points:



Draw an upside-down U-shaped curve through those two points:



Edwin