Answer: 9
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Work Shown:
f(x) = x-7
f(4) = 4-7
f(4) = -3
We can see that f(4) and -3 are the same number. Because of this, we can replace f(4) with -3
This will have us go from g( f(4) ) to g( -3 )
Then we plug x = -3 into the g(x) function
g(x) = x^2
g(-3) = (-3)^2
g(-3) = 9 is the final answer
Again, since -3 and f(4) are the same thing, we can replace that '-3' in g(-3) to get
g( -3 ) = 9
g( f(4) ) = 9
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An alternative route:
g(x) = x^2
g( f(x) ) = ( f(x) )^2 .... replace every x with f(x)
g( f(x) ) = ( x-7 )^2 .... plug in f(x) = x-7 for the right hand side only
g( f(4) ) = ( 4-7 )^2 ... plug in x = 4
g( f(4) ) = (-3)^2
g( f(4) ) = 9