Answer:
![y\in (-\infty ,5]](https://tex.z-dn.net/?f=y%5Cin%20%28-%5Cinfty%20%2C5%5D)
Step-by-step explanation:
In this problem, we need to write "Twenty times y is at most 100 in interval notation
".
20 times y means, 20y
Atmost means an inequality which is 
ATQ,

i.e.

We can also write it as :
![y\in (-\infty ,5]](https://tex.z-dn.net/?f=y%5Cin%20%28-%5Cinfty%20%2C5%5D)
Hence, the required interval notation is
.
We have equation:
t=20x+31
x is number of years after 1997.
To calculate number of laptops in 2005:
x=2005-1997
x=8
t=20*8+31
t=160+31
t=191
In year 2005 school had 191 laptops.
Like this? Brainliest if I got it? :) it’s ok if u don’t
Hi
i have just tried this equation just now.
tell me if i made some mistakes please
S=1.68-0-0+2x
A=1.68+2x