The fire department has seen an increase in smoke detector sales since 2015. In 2015, they sold 350 detectors which is up from the previous year by 105%. How many did they
sell in the previous year?

Step-by-step explanation:

Given the amount of detectors sold in the current year = 350

percent increment = 105%

To get the amount sold the previous year, we will use the expression;

(105% of x) + x =  350

1.05x = 350 + x

1.05x + x = 350

2.05x = 350

x = 350/2.05

x = 170.7

Hence the amount sold the previous year was 170.7 detectors

i am thinking c. sorry if im wrong .

step-by-step explanation:

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8