Question

What is the value of the expression f(-3) + 2f(-1) - f (4) PLEASE HELP NO LINKS

Answer 1

Answer:

22

Step-by-step explanation:

Find f(-3) :

f(x) = x² + 2x for x ≤ -3

That means for those values of x, less than or equal to -3, this is the function.

So, f(-3) = (-3)² + 2(-3) = 9 - 6 = 3

Now, f(-1) :

From the given data, we see it is: f(x) = 2 $(\frac{1}{3} )^{2x}$

We take this because -1 lies between -3 and 4.

Now, f(-1) = 2 $(\frac{1}{3} )^{2(-1)}$

 => $f = (-1) = 2(3)^{2} = 2 (9) = 18$

For f(4) :

Clearly, the function is: $f (x) = \frac{2x - 5}{x-7}$

$f (4) = \frac{2(4)-5}{4-7} = \frac{3}{-3} = -1$

Therefore, f(-3) + f(-1) - f(4) = 3 + 18 - (-1) = 3 + 18 + 1 = 22.