 This video will talk about how to grab on a Cartesian coordinate. So in a Cartesian coordinate, it's two number lines. They're called axes. This one up here is called the y-axis, and this one here is called the x-axis. The horizontal is the x-axis, and it looks like a normal number line with the positive numbers on the right and the negative numbers on the left. And a vertical axis is the y-axis, with the positive numbers up at the top, and the negative numbers down at the bottom, and then right in the middle where they cross is where the zeros are for each number line, and that's called the origin, and it's the point zero-zero. This ordered pair is what that zero-zero is called, and it's made up of this x and y that you see here. X always comes first, and then the y. So let's look at some graphs. This point A here, when you start at the origin, whenever you're graphing, you always start at the origin, and then you count how far over to the left and how far over to the right you went. But we didn't go anywhere left or right, so this would start out in the x-direction. We went zero units, and then from there we moved up one, two, three, four units in the y-direction, or up. So that point right there, A, is zero-four. Let's try B. We start at the origin again, and then we count over, and we went one, two, three, four, five to the left, and you can see the negative five right below there tells you that it's a negative five in the x-direction, but then we didn't move up or down, so that's going to be zero in the y-direction. So let's try C. This time we get to move both directions, so we go over until we're right above it, and that looks like a three. So that's the x coordinate, and then we went down one, two, three, four. You can see that we're right over from negative four because we went down. It's a negative number, so that ordered pair is three negative four. D, we go over to six, we're right below, right above the six, so the x-coordinate is the six. Always do x first, and then we go up y one, two, three, four, five, six, seven. So that's the ordered pair, six, seven, and finally over here at E, we went over to negative two in the x-direction, and then we went down one, two, three, four, five, six, seven, eight. We're straight across from negative eight, so that point is negative two, negative eight. Remember, it's always x first, and then y. So let's try plotting these points over here. Negative two, negative three means we go negative two in the x-direction, and then from there we turn the corner and go negative three, or down three in the y-direction. So negative is left, so we go one, two in the x-direction, and then from there we're going to go down one, two, three. So there, right there, is our f. That's negative two, negative three. G says four, negative one, so we go across to four, and then down one, because it's a negative one, and this point right here will be our g. H is zero, negative five, so we start at the origin again, always start at the origin. We can't go anywhere left and right, because it's a zero, and then we go down five to this point right here at negative five, that's zero, negative five, and that's my h, and then finally j is three zero, so we go three in the right direction where the positive numbers are, and then it says zero, so we don't go up or down, and we have this point right here, which would be our j. So how do we apply that? Well, if I have an equation, I can graph an equation by just picking some points. It takes two points to define a line, three points to make it even more accurate. So let's try. This says that x is negative one, so I'm going to come in here and say two times x, which I now know to be negative one, minus two. Two times negative one is negative two, minus two would be negative four, so my x was negative one, and my y was negative four. All right, try again, find another point. So I don't know y, but I know x, two times zero, which is x minus two, that's zero minus two, or negative two, and the ordered pair would be zero for the x, negative two for the y. Y is equal to two times one, when x is one, minus two, so two minus two would be zero, so we have the point one, zero, and finally, y is equal to two times two when x is two, minus two, or four minus two, which is two, so x is two, y is two. And now we want to plot those points. So negative one, and then down to negative four would be one point on my line, zero, negative two, so start at the origin, and then just go down two, because we didn't go left or right, one, go over to one, and then zero, so we just stay right there on the x-axis, and then two, two, we go over to two, and then we go up two, and it would be this point right here, and we should feel like we did it correctly, because all our points lie in a line. Didn't draw my line very well, but you can see that it's a line. All right, so let's interpret some points, some ordered pairs. So it asks us to write an ordered pair for each year, so where x is the number of years since 2000, and y is the number of victims. So this is the number of years since 2000, so it would be zero, that would actually be the year 2000, and the number of victims would be 653. X is the number of years, y is the number of victims, so one and 862, and two goes with 911, and three goes with 819 victims, and four years after 2000, there were 804 victims. It says now, interpret the first and last ordered pairs. Well, our first ordered pair was 0, 653. But remember that x is number of years since 2000, so this is my x, and it's zero, so it means the year 2000, and then y is the number of victims, and this is a y, so it means in 2000, there were 653 victims. The last ordered pair is this last one over here, that's 4 and 804. Again, this is x, and x means years since 2000, so it's going to be the year 2004, and in 2004, there were y, which is number of victims, so 804 victims, or I've missed my there were, there were 804 victims. And finally, it says plot the ordered pairs to form a scatter plot. Scatter plot just means that it's not going to probably be perfect. This is my x, and that's years since 2000, and this is my y, and that's the number of victims, and graphs don't have to be perfect. This would be zero here, and this would be 1, 2, 3, 4, and if I draw a little squiggle line here, it means that I'm going to have a gap, not starting at 1, and I'm going to start, and I'm going to call it, I'm going to say 600, and then maybe 650, and then 700, and 750, and 800, and 850, and I can just kind of guesstimate. So in the year zero, there were 653, so it's just a little bit beyond 650, and then 1 would be 862, so that's above my 850, and somewhere above it, then have to be perfect. It's just a scatter plot. 2 would be 911, oh I didn't go up high enough, this would be 900, so it would be just a little bit higher than that. Then we have 3819, so here's 800, it would be just a little bit above that, and then 4804, again here's 800, and it's even going to be less than the one before. So that's a nice little scatter plot, not perfect, but it just kind of shows you the pattern that's happening.