Lindsay C.

asked • 12/15/17

Let g(x) = -4x2 - 3x - 7. Find the following: g(-1) , g(0) and g(3) show all work for each of them

Show how to solve each of them 

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John M. answered • 12/15/17

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First, let's clean up the equation.
 
g(x) = -4 x 2 - 3x - 7
-4 x 2 = -8
g(x) = -8 - 3x - 7
-8 - 7 = -15
g(x) = -15 - 3x
 
Now substitute -1 for x.
 
g(-1) = -15 - 3(-1)
g(-1) = -15 - -3
g(-1) = -12
 
Now do the other two by substituting 0 and 3 for x.
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Lindsay C.

It's not -4x2 it's -4x^2. I don't know how to write it from a computer. I'm sorry. I guess I could say it as -4x to the 2nd power. The 2 goes to the side of the x at the top
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12/15/17

Michael J.

Use the superscript option in the word processing pane.
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12/15/17

John M.

tutor
Oh, that's why it seemed weird.  So it should be 
 
g(x) = -4x2 - 3x - 7
 
You still do the same thing, substitute the number for x then multiply and add.
 
g(-1) = -4(-1)2 -3(-1) -7
g(-1) = -4(1) +3 - 7
g(-1) = -4 + 3 - 7
g(-1) = -8
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12/15/17

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