Question

the price of a certain item was $10 in 1990 and it has gone up by $2 oer year since 1990. if this trend continues, in what year will the price be $100?

Answer 1

Model the function as a linear equation:
y=2x+10
Where y=price of item, and x=years since 1990.
Plug in 100 for y.
100=2x+10
2x=90
x=45
45 years after 1990 so 45+1990 or 2035.

In 2035, the price of the item will be $100

Hope this helps :)