Systems of Inequalities

Hi, I'm new to freemathhelp.com so I hope I use this right. I'm working on system of inequalities and I don't know how to get started.
I have y >_ x That's y is greater than or equal to x
y<_ -x+3 This is y < or equal to -x+3

I know how to graph and I know how to shade the common area but I don't know how to get to that point. Can you get me started? Or tell me an area where I can go to read up on it?

thanks for any assistance you can provide.

2practl said:

Hi, I'm new to freemathhelp.com so I hope I use this right. I'm working on system of inequalities and I don't know how to get started.
I have y >_ x That's y is greater than or equal to x
y<_ -x+3 This is y < or equal to -x+3

I know how to graph and I know how to shade the common area but I don't know how to get to that point. Can you get me started? Or tell me an area where I can go to read up on it?

thanks for any assistance you can provide.

Click to expand...

Do you know how to plot y = x ?

and


Do you know how to plot y = -x + 3 ?

Not without having numbers for y and x. If y=x do I pick any number i.e.3 and 3 is x and 3 is y? I can plot both those and draw a line. But don't know about the y = -x+3.

graphing y = x :

x has a slope of 1 (the one is understood, not written) and the y intercept is 0, thus it passes through the origin.

2practl said:

Not without having numbers for y and x. If y=x do I pick any number i.e.3 and 3 is x and 3 is y? I can plot both those and draw a line. But don't know about the y = -x+3.

Click to expand...

yes, when x is 3, y is 3, when x is -250.4, y is -250.4

graphing y = -x + 3:

3 is your y intercept: where the line will cross the y axis, -x has a slope of negative one, so it will slant the opposite direction as the positive. to graph it, either use the slope and the intercept, or plug in a number as x, move your point that far to the right or left, then solve the function for y, and move the point up or down however far the answer tells you to:

Ex: y = -x + 3, @ x = 2

y = -(2) + 3

y = 1

That helps, thank you. I do kind of remember the slope intercept thing.

Thank you, I may be back later with something more complex.