Answer:
the third one
Step-by-step explanation:
4n² - 16n - 84 = 0
Multiply both sides by 1/4 :
n² - 4n - 21 = 0
Add 21 to both sides:
n² - 4n = 21
Complete the square by adding 4 to both sides:
n² - 4n + 4 = 25
(n - 2)² = 25
Solve for n :
n - 2 = ± √25
n - 2 = ± 5
n = 2 ± 5
Then n = 2 + 5 = 7 or n = 2 - 5 = -3.
24 pine trees in equal rows, with the number of trees in each row being 10 or more than the number of rows.
Hugo could have planted 12 trees in 2 rows.