Use the graph to find the value.
-(f · g)(6)
A) -8
B) 6
C) 8
D) -6

Question

Use the graph to find the value. 
-(f · g)(6)
A) -8 
B) 6 
C) 8 
D) -6

Quizplus · Accepted Answer

To find (f · g)(6), we need to multiply the y-values of f and g at x=6, and then add them. At x=6, f has a y-value of -1 and g has a y-value of -7. Therefore, (f · g)(6) = -1(-7) = 7. However, we can see from the graph that the point (6,7) is reflected over the x-axis. This means that the point (6,-7) is also on the graph, and (f · g)(6) could also be equal to -7+1 = -6. The graph does not provide enough information to determine which of these is the correct value, but C (-7 or 7) is the closest answer choice to both possible values. To find (f · g)(6) we need to multiply the output of g(6) with the output of f applied to the output of g(6). From the graph, we can see that g(6) = -2 and f(-2) = 4, thus (f · g)(6) = f(g(6)) = f(-2) = 8. Therefore, the best choice is C) 8.

Use the Graph to Find the Value