What is an example of area ( in math ) in a real-life situation?

Find the slope of the line below . enter your answer as a fraction or decimal. use a slash mark ( / ) as the fraction bar if necessary

The weight of an object in a particular scale is 175.2 lbs. the measured weight may vary from the actual weight by at most 0.1 lbs. what is the range of actual weights of the object

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)