Math Destroyer Question

[Ibraiz]

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Can somebody please help me understand how they got the answer and how is it that "F(x) must be x(squared)"

http://img375.imageshack.us/img375/332/mdestroyertest2q16.jpg

 

[UndergradGuy7]

If you have an equation like x+1. We can say that G(x) = x+1.

So if I say what is G(1)? You just plug in 1 into the equation and solve. So G(1)=1+1 = 2.

So in this problem they give you G(x)=x-3.

Then they say G(F(x))= x^2 -3

That's like what we did above. They plugged in something "f(x)" into G(x) and got x^2 - 3. What can you plug into x-3 to get x^2 - 3? This is F(x). So if you plug in x^2 into x-3 you get x^2-3.

So you know f(x)=x^2 so 3^2= 9.

 

[Ibraiz]

Thanks, make sense

I have another question. How do they come up with the probability of rolling a sum of six in a pair of dice is 5/36?



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[herkulease]

how many possible combination can you make that add up to six?

1,5
5,1
2,4
4,2
3,3

 

[Ibraiz]

how many possible combination can you make that add up to six?

1,5
5,1
2,4
4,2
3,3

I was thinking the combination 1,5 and 5,1 would count as one combination and same goes for 2,4 and 4,2 so I was only coming up with 3 combinations:
1,5
2,4
3,3
Now it makes sense when you explained. Thanks