Find the requested value.

Question

f(-5) for f(x) = {7x     if x ≤ -1

                      {x-9    if x > -1

Answer 1

Hi Jay,

 

we have to find the value for f(-5)

 

The equation f(x)=7x gives the value of f(x) when x is less than or equal to -1.

 

The equation f(x)=x-9 gives the value of f(x) when x is greater than -1.

 

since -5 is less than -1

 

so we will take the equation f(x)=7x to find the value for f(-5)

 

f(-5)=7(-5)=-35

Answer 2

In this example we will be substituting the value (-5) for x in the expression given.

 

The critical question is:

 

is -5 more or less than -1?

 

If it is less, then you use the first expression:  f(x) = 7x.

 

If it is more, then you use the second expression:  f(x) = x-9.

 

The actual numerical evaluation will proceed exactly as you would expect after that point.