B. 10
To expand (2a-5b)², we use the formula (a - b)² = a² - 2ab + b².
In this case, a = 2a and b = 5b. Plugging into the formula:
(2a-5b)² = (2a)² - 2(2a)(5b) + (5b)²
= 4a² - 20ab + 25b²
Therefore, the coefficient of ab is -20.
In the expansion of (2a-5b)² the coefficient of ab is
A. 20
B. 10
C. -20
D. -10
1 answer