In: Math
Find f(x) if f is a linear function that has given properties.
f(-1)=1, f(3)=9
f(x)=
Given is a linear function where and
We know any linear function has to be of the form:
-----(1)
where a is the coefficient of x and b is a constant
f(-1) and f(3) are obtained by substituting x=-1 and x=3 in (1) respectively.
Substituting x=-1 in (1):
-----(2)
Substituting x=3 in (1):
-------(3)
Rewriting (3) to obtain the value of b:
-----(4)
Substitute (4) in the place of "b" in (2)
------(5)
Sunstitute (5) in (4)
Since
-----(6)
Substituting (5) and (6) in (1)
So, the linear function is f(x)=2x+3