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If f(x) = 7x - 3 and g(x) = x^2, what is (g° 0(1)?

User Daniel De Freitas
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2 Answers

13 votes
13 votes

Hello,


f(x)=7x-3\\g(x)=x^2\\\\(fog)(x)=g(f(x))=g(7x-3)=(7x-3)^2=49x^2-42x+9\\\\(gof)(x)=f(g(x))=f(x^2)=7x^2-3\\\\(fog)(0)=g(f(0))=49*0^2-42*0+9=9\\\\(gof)(0)=f(g(0))=7*0^2-3=-3\\

Since i don't know what is (g°O(1) and you haven't correct your question ,

i has put the 2 possibles answsers.

User Ecg
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10 votes
10 votes

( f ∘ g ) ( x ) is equivalent to f ( g ( x ) ) . We solve this problem just as we solve f ( x ) . But since it asks us to find out f ( g ( x ) ) , in f ( x ) , each time we encounter x, we replace it with g ( x ) . In the above problem, f ( x ) = x + 3 . Therefore, f ( g ( x ) ) = g ( x ) + 3 . ⇒ ( f ∘ g ) ( x ) = 2 x − 7 + 3 ⇒ ( f ∘ g ) ( x ) = 2 x − 4 Basically, write the g ( x ) equation where you see the x in the f ( x ) equation. f ∘ g ( x ) = ( g ( x ) ) + 3 Replace g ( x ) with the equation f ∘ g ( x ) = ( 2 x − 7 ) + 3 f ∘ g ( x ) = 2 x − 7 + 3 we just took away the parentheses f ∘ g ( x ) = 2 x − 4 Because the − 7 + 3 = 4 This is it g ∘ f ( x ) would be the other way around g ∘ f ( x ) = 2 ( x + 3 ) − 7 now you have to multiply what is inside parentheses by 2 because thats whats directly in front of them. g ∘ f ( x ) = 2 x + 6 − 7 Next, + 6 − 7 = − 1 g ∘ f ( x ) = 2 x − 1

User Shiju Shaji
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