Last week, the value of an investment changed at a rate of –$0.80 each hour. After how many hours was the total change in value –$3.60?

4 hours

Step-by-step explanation:

3.6 / .8

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225

the inequality is:

250c+180g≥950

step-by-step explanation:

let c denotes the number of days in a week   miyoko worked as a cryptographer.

and g denotes the number of days in a week she works as a geologist.

now we are given that she earns $250 for every day she works as a cryptographer,and earns $180 for every day she works as a geologist.

now miyoko's goal is to earn more than $950 this week.

hence, the inequality could be represented as:

250c+180g≥950