b. Given f(x) = x - 5 and g(x) = x ^ 2 + 2x - 1 find f(g(x)) and g(f(x)) Expand and simplify your answers. [4 marks]
Question
Answer:
To find f(g(x)), we substitute the expression for g(x) into f(x):
f(g(x)) = f(x^2 + 2x - 1)
Now, we substitute the expression for f(x) into the above equation:
f(g(x)) = (x^2 + 2x - 1) - 5
Simplifying further:
f(g(x)) = x^2 + 2x - 1 - 5
f(g(x)) = x^2 + 2x - 6
Therefore, f(g(x)) = x^2 + 2x - 6.
Now, let's find g(f(x)). We substitute the expression for f(x) into g(x):
g(f(x)) = g(x - 5)
Now, we substitute the expression for g(x) into the above equation:
g(f(x)) = (x - 5)^2 + 2(x - 5) - 1
Expanding and simplifying further:
g(f(x)) = x^2 - 10x + 25 + 2x - 10 - 1
g(f(x)) = x^2 - 8x + 14
Therefore, g(f(x)) = x^2 - 8x + 14.
solved
general
11 months ago
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