Answer:
A
Step-by-step explanation:
49y² - x² ← is a difference of squares and factors in general as
a² - b² = (a - b)(a + b) , then
49y² - x²
= (7y)² - x²
= (7y - x )(7y + x) → A
a= -40
Answer:The height of the building is 30ft
B.20
hope it's helpful ❤❤❤❤❤❤❤❤❤❤
THANK YOU.
