Answer: 4x² + 68x + 289
Explanation:
f(3x - 5) = 6x + 7
How can we change 3x into 6x? by multiplying by 2
Consider that f(x) = 2x, then f(3x - 5) = 2(3x - 5)
= 6x - 10
We are close, but not quite there. How can we change -10 into +7? by adding 17
Now, consider that f(x) = 2x + 17, then f(3x - 5) = 2(3x - 5) + 17
= 6x - 10 + 17
= 6x + 7
Bingo! So, f(x) = 2x + 17
Now, let's find f²(x) --> (2x + 17)²
= (2x + 17)(2x + 17)
= 4x² + 68x + 289