ALGEBRA
FUNCTION NOTATION (MATH 130)
#29) PROBLEM:
Find
()()
h
fhf 22 −+ for the function
(
)
79
+
=
xxf .
STUDENT HAD THE FOLLOWING:
The student didn’t know what to substitute for what. She could not read function
notation correctly.
TUTOR STORY:
Tutor Kurt started by explaining to the student that f(2) means “substitute number 2 for
every x you see in function f.” Similarly, f(2+h) means “substitute the expression (2+h)
for every x you see in the same function f.” Kurt gave the student several other examples
illustrating the same concept. Then the student completed the problem:
()()()()
9
9
25925
729729
=
=
−+
=
+−++
h
hh
hh
h
Therefore,
()()
9
22 =
−+
h
fhf answers the question in this problem.
END
