Part (a)
Locate x = -1 on the x axis. Draw a vertical line through this x value until you reach the f(x) curve. Then move horizontally until you reach the y axis. You should arrive at y = 4. Check out the diagram below to see what I mean.
Since f(-1) = 4, this means we can then say
g( f(-1) ) = g( 4 ) = 4
To evaluate g(4), we'll follow the same idea as what we did with f(x). However, we'll start at x = 4 and draw a vertical line until we reach the g(x) curve this time.
Answer: 4
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Part (b)
We use the same idea as part (a)
f(-2) = 5
g( f(-2) ) = g(5) = 6
Answer: 6
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Part (c)
Same idea as the last two parts. We start on the inside and work toward the outside. Keep in mind that g(x) is now the inner function for this part and for part (d) as well.
g(1) = -2
f( g(1) ) = f(-2) = 5
Answer: 5
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Part (d)
Same idea as part (c)
g(2) = 0
f( g(2) ) = f( 0 ) = 3
Answer: 3