Given that f(x) =2x _5 and g(x) = x +3, find f_1(x), fg(x), fg(4)

Answer 1

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Given that
f(x) = 2 x - 5
and
g(x) = x +3,
find f^-1(x),
f g(x),
fg(4)
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f^-1(x)
reverse x and y
x =2 y - 5
2 y = x+5
y = x/2 + 2.5

f (g(x) ) = f( x+3) = 2(x+3) - 5 = 2 x + 1

f( g(4)) = 8+1 = 9
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check
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g(4) = 4+3 = 7
f(7) = 14 - 5 = 9 sure enough