Question 111749
Use the graph of y = -x^+4x+5 to answer the following:
-x^+4x+5= 0 explain how you obtain your answers by looking at the graph:
Does this function have a maximum or minimum? 
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Graph Y = -x^2 + 4x + 5. substitute values of x and find y from x = -2 to x = +6
It should look like this:
{{{ graph( 300, 200, -4, 8, -10, 10, -x^2+4x+5) }}}
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It says -x^2 = 4x + 5 = 0, Explain what values of x substituted in the equation, will give you a value of 0 for y. You can look at the graph and see that when x = -1 and when x = +5, it crosses the x axis which is y = 0
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You can see from the graph that this function has a maximum which occurs when x=+2
y will = 9, and this is the maximum. A good thing to remember, when the coefficient of x^2 is negative you have a maximum and when it is positive you have a minimum
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Did this make sense to you?