Let f of x is equal to negative 4 x and g of x is equal to 5 x squared Andrew finds the composition open bracket f circ g close bracket times x as shown. What error did Andrew make? is equal to 5 times open paren negative 4 x close paren squared is equal to 5 times open paren 16 x squared close paren is equal to 80 x squared
Answer
A
The coefficient of f of x was squared incorrectly.
B
The negative sign for f of x was not included in the calculation.
C
The composition was done in the incorrect order.
D
The coefficients should be multiplied and then squared.
Explanation
For (f ∘ g)(x), apply g first and then f: f(g(x)) = f(5x²) = −4(5x²) = −20x². Andrew instead calculated g(f(x)) = 5(−4x)², which reverses the order of the composition. So his error was doing the composition in the incorrect order.
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