Final answer:
The simplified expression for 2f(x+3) - 7 where f(x) = 10x - 9 is 20x + 35. To simplify the expression 2f(x+3) - 7, substitute the given expression for f(x), simplify the expression inside the parentheses, distribute the 2 to both terms inside the parentheses, and combine like terms.
Step-by-step explanation:
To simplify the expression 2f(x+3) - 7 where f(x) = 10x - 9, we first substitute x+3 into the function f to find f(x+3). The function, therefore, becomes f(x+3) = 10(x+3) - 9 which simplifies to 10x + 30 - 9. Upon simplification, this gives us 10x + 21.
Next, we multiply this expression by 2 which gives us 2(10x + 21) resulting in 20x + 42. Finally, we subtract 7 from this result. The expression simplifies to 20x + 35.