Answer:
-1
Step-by-step explanation:
2x² - 5x + 7 is subtracted from x² + 2x - 11, so
(x² + 2x - 11) - (2x² - 5x + 7)
x² + 2x - 11 - 2x² + 5x -7 (Distribute the negative)
-x² + 7x - 18 (Combine like terms)
The leading coefficient is the coefficient of the first term, so it is -1.