He would water his plant on the 15th day because u need to find how what can divide into both of them and it had to be the least so 15
Answer:
B 9, -9
Step-by-step explanation:
x^2 - 81 = 0
Add 81 to each side
x^2 = 81
Take the square root of each side
sqrt(x^2) = sqrt(81)
x = ±9
3000
640x3 = 1920
90x12 = 1080