F(x)=x-5
g(x) = 2x+1
Write the expressions for (f-g)(x) and (f+g)(x) and evaluate (fg)(4).

(f - g)(x) = -x - 6

(f + g)(x) = 3x - 4

(f*g)(4) = -9

Step-by-step explanation:

These are your equations:

f(x) = x - 5

g(x) = 2x + 1

To find (f - g)(x), subtract g(x) from f(x).

(f - g)(x) = x - 5 - (2x + 1)

(f - g)(x) = x - 5 - 2x - 1

(f - g)(x) = -x - 5 - 1

(f - g)(x) = -x - 6

To find (f + g)(x), add f(x) with g(x).

(f + g)(x) = x - 5 + 2x + 1

(f + g)(x) = 3x - 5 + 1

(f + g)(x) = 3x - 4

To find (f*g)(4), you need to first find (f*g)(4).  You can do this by multiplying f(x) wih g(x).

(f*g)(x) = (x - 5)(2x + 1)

(f*g)(x) = 2x² - 9x - 5

Now that you have (f*g)(x), solve with x as 4.

(f*g)(4) = 2(4)² - 9(4) - 5

(f*g)(4) = 2(16) - 9(4) - 5

(f*g)(4) = 32 - 36 - 5

(f*g)(4) = -9