Final answer:
To find the equivalent expression of A² - B, simplify and square A, substitute B, and then subtract B from A². The result is 9x² - 28x + 11.
Step-by-step explanation:
To find the expression equivalent to A² - B, we first need to simplify and square A. A = 3x - 4, so A² = (3x - 4)² = 9x² - 24x + 16. Next, we simplify and substitute B in the expression. B = 5 + 6x - 2x = 5 + 4x. Now we can subtract B from A²: A² - B = (9x² - 24x + 16) - (5 + 4x) = 9x² - 28x + 11.