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FIND f(g(x)) and g(f(x)) and determine wether the pair of functions f and g are inverses of each other?
f(x)=7x-4 and g(x)=x+7/4
a. f(g(x))=
Simplify answer
2 Answers
- JuanLv 68 years agoFavorite Answer
f(x) = 7x - 4
g(x) = x + (7/4)
f(g(x)) just means plug [x + (7/4)] where their is
an x in the f function therefore
f(g(x)) = 7[x + (7/4)] - 4
7x + (49/4) - (4)
7x + (49/4) - (16/4)
7x + (33/4)
g(f(x)) just means plug (7x - 4) where their is
an x in the g function therefore
g(f(x)) = (7x - 4) + (7/4)
7x - (16/4) + (7/4)
7x - (9/4)
To find if there inverse make
one of the equations set to the answer y
y = 7x + (33/4)
now switch the variable
x = 7y + (33/4)
solve for y
x = 7y + (33/4)
x - (33/4) = 7y
y = (x/7) - (33/28)
There not inverse functions of each other
- chumpLv 58 years ago
f(g(x)) ã 7(x+7/4) - 4 ã [(7x + 49)/4] - 4
g(f(x)) ã (7x-4+7)/4 ã (7x+3)/4
The inverse of y ã 7x - 4 is defined as x ã 7y - 4 and isolating y produces y ã (x+4)/7 which is not g(x).
If the fuctions were inverses then f(g(x)) ã g(f(x)) ã 1.