



 
Hi Kenneth, I am going to illustrate with a different function. Let $g(x) = 4x^3  7 x^2$ and find $g(2x  1).$ The action of the function $g$ is described by the expression $g(x) = 4x^3  7 x^2.$ In this expression $x$ is the input to the function and the description says that you cube the input, multiply by 4 and then subtract 7 times the cube of the input. Hence if you input the number 5 then the cube of 5 is 125 so you multiply 125 by 4 and then subtract 7 times the square of 5. Hence \[g(5) = 4 \times 5^3  7 \times 5^{2} = 675.\] Likewise \[g(2) = 4 \times (2)^3  7 \times (2)^2 = 60.\] If the input to the function $g$ is $2x1$ then $g$ cubes the input to get $(2x1)^{3},$ multiplies by 4 and then subtracts 7 times the square 0f the input. Hence \[g(2x  1) = 4 \times (2x  1)^3  7 \times (2x  1)^{2}.\] I should expand and simplify the above expression. Can you solve your problem now?  


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