Question

Could someone help explain graphing and solving inequalities? I really don't understand how they work. Here's an example: 8>-x≥-9

Answer 1

Solving an inequality is just like solving an equation except remember that if you divide by a negative you have to switch the inequality sign. Whatever you do to one side you must do to the other.

with the given example x is anything greater or equal to -9 but less than 8. you can write that like this:

[-9, 8) because it includes -9, but excludes 8. On the graph there would be a closed circle over -9, and an open circle on 8, including everything in between that x could be.

Answer 2

Well in this case, -x is your function. So y = -x. The inequalities show the range of x values that you want to look at. So you would plug in each value, y = -(8), y = -(-9). And those are the values of x you limit your graph to. So the graph would be a normal graph of y = -x but you would stop it where the inequality tells you to, in this case [-9,8). The [ shows that -9 is included in your graph, and the ) shows that 8 is not included. This relates to the equal to or greater than portion of the inequality. Greater/Less than will be excluded, so use ( or ). Greater/Less than or equal to is included, so use [ or ].

Answer 3

Ok got it. Thank you for your help :)