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If $t$ is a real number, what is the maximum possible value of the expression $-t^2 + 8t -4$?

 Jan 23, 2018

Best Answer 

 #1
avatar+8071 
+2

the maximum value occurs when...

 

t   =   -8 / [ 2(-1) ]

 

t   =   -8 / -2

 

t   =   4

 

When  t  =  4 ...

 

-t2 + 8t - 4

 

=  -42 + 8(4) - 4

 

=  -16 + 32 - 4

 

=  12

 

Here's a graph:   https://www.desmos.com/calculator/qdghoci3o9

 Jan 23, 2018
 #1
avatar+8071 
+2
Best Answer

the maximum value occurs when...

 

t   =   -8 / [ 2(-1) ]

 

t   =   -8 / -2

 

t   =   4

 

When  t  =  4 ...

 

-t2 + 8t - 4

 

=  -42 + 8(4) - 4

 

=  -16 + 32 - 4

 

=  12

 

Here's a graph:   https://www.desmos.com/calculator/qdghoci3o9

hectictar Jan 23, 2018

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