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avatar+63 

g(X) = -4x2 -3x + 2 

 

determine G(-2)

 Nov 15, 2019
 #1
avatar+63 
0

hectictar can you help me again please??

 Nov 15, 2019
 #8
avatar+669 
+1

awesome explanation hectictar! ! ! 

ok so here's the trick for these though:

remember just like hectictar said: "Replace every x with -2" 

We know that we have a function: \(g(x) = -4x^2 -3x + 2 \)

and you also need to be very careful with PEMDAS

now! plug in -2 everywhere you see x 

and solve!! 

 

essentially just think of your g(x) as your y value.......
imagine a graph and i gave you the x coordinate (which you plugged in to your g(x) shhhh) and asked you to find the y coordinate 

how would you locate the y coordinate given the x coordinate of your point? :)

but what if you were given \(f(x)=3x+5x-2+x^2\)
and told to find the \(f(-3)\)
can you tell me how that would work K19? :D 

Nirvana  Nov 15, 2019
 #2
avatar+8829 
+2

g(x)  =  -4x2 - 3x + 2

                                              Replace every  x  with  -2

g(-2)  =  -4(-2)2 - 3(-2) + 2

 

 

Now what do you get if you calculate the right side of that equation?

 Nov 15, 2019
 #3
avatar+63 
+1

i got 

 

g(-2) = 16 - 6 + 2 

 

is that right??

 Nov 15, 2019
 #4
avatar+8829 
+2

Very close!! But be careful with your negative signs!

 

g(-2)  =  -4(-2)2 - 3(-2) + 2

                                              Negative two squared is equal to positive four.

g(-2)  =  -4(4) - 3(-2) + 2

                                              Negative four times positive four equals negative sixteen.

g(-2)  =  -16  - 3(-2) + 2

                                              Negative three times negative two equals positive six.

g(-2)  =  -16  +  6  +  2

 

Now just calculate negative sixteen plus six plus two!

 Nov 15, 2019
 #5
avatar+63 
+1

i then got 

 

g(-2) = -8 

 

as my final answer?

 

is that better lol

 Nov 15, 2019
 #6
avatar+8829 
+2

Perfect!! smiley

hectictar  Nov 15, 2019
 #7
avatar+63 
0

sry to bug you but i will post another question in like a minute and this one i think i understand better i just need clarification 

 Nov 15, 2019

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