Expert: Sherman D. - 9/22/2008

Question
Hello, I was doing homework and right now its about finding the domain and range and zeros of an equation. I was doing ok until I saw a graph with open dots on it. It looks a little like this, 0----(closed dot), here's my question, what does it mean? Thank you for your time.

Answer
Are you talking about a line graph with dots, that just means this

If the left side has an open dot, as in its just a circle, then it stands for < or >, if it is closed, which is a shaded circle, then it is <= or >=.

let say that the left side lands on -5 and the right side lands on 3, the -5 has an open dot, and the right side is closed, then you have

-5 < x <= 3

however if the 0 is suppose to be a zero and not an open dot and the line is dashed, then

0 < x <= (whatever the closed dot is on)

just google, inequality and also try google the word closed/open dot also solid/dashed line.

if the graph is a parabola, then use the formula ax^2 + bx + c, and see what you come up with. The zeros are where the dotted graph crosses the x-axis, the domain is infinite to the right and left of the vertex, and the range is where the vertex starts, then you just have to put < or > depending if the graph opens upwards or downwards.

by the way, to find "a" and "b" in ax^2 + bx + c, you just have to use trial and error, also "c" is where the dotted graph crosses the y-axis.

www.quickmath.com can graph inequalities for you.