Answer:
4 sqrt(5)
Step-by-step explanation:
7 sqrt(5) - 3 sqrt(5)
These are like terms so we can subtract
b
(A) 37.7 feet sorry if i get it wrong
![A = A_{0}*( \frac{1}{2})^(t/t_{\frac{1}{2}) [tex]A= Amount of Substance Left A_{0} = Initial Amount of Substance t = Time Taken t_{\frac{1}{2}} = Half-Life of the Substance](https://tex.z-dn.net/?f=A%20%3D%20A_%7B0%7D%2A%28%20%5Cfrac%7B1%7D%7B2%7D%29%5E%28t%2Ft_%7B%5Cfrac%7B1%7D%7B2%7D%29%20%20%5Btex%5DA%3D%20Amount%20of%20Substance%20Left%20A_%7B0%7D%20%3D%20Initial%20Amount%20of%20Substance%20t%20%3D%20Time%20Taken%20t_%7B%5Cfrac%7B1%7D%7B2%7D%7D%20%3D%20Half-Life%20of%20the%20Substance)