Find Value of c

**sharkman** · August 31st 2009, 06:12 AM

A certain function has the form f(x) = ax + b
where a and b ≠ 0.

If f(5) = 1, f(-3) = 25 and f(c) = 0, what is the value of c?

**e^(i*pi)** · August 31st 2009, 06:14 AM

Originally Posted by sharkman

A certain function has the form f(x) = ax + b
where a and b ≠ 0.

If f(5) = 1, f(-3) = 25 and f(c) = 0, what is the value of c?

$f(5) = 5a + b = 1$

$f(-3) = -3a + b = 25$

Solve for a and b simultaneously

$f(c) = ac + b = 0$

Sub in the now known values of a and b to find c.

**sharkman** · August 31st 2009, 07:41 AM

Originally Posted by e^(i*pi)

$f(5) = 5a + b = 1$

$f(-3) = -3a + b = 25$

Solve for a and b simultaneously

$f(c) = ac + b = 0$

Sub in the now known values of a and b to find c.

How did you determine that this is a system of two equations?

**e^(i*pi)** · September 1st 2009, 11:36 AM

Originally Posted by sharkman

How did you determine that this is a system of two equations?

Two values for f(x) were given and there are also two constants in f(x)

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