Let's quickly review the steps for writing an equation given two points:
Slope-intercept form linear equations Standard form linear equations Point-slope form linear equations Video transcript A line passes through the points negative 3, 6 and 6, 0. Find the equation of this line in point slope form, slope intercept form, standard form.
And the way to think about these, these are just three different ways of writing the same equation. So if you give me one of them, we can manipulate it to get any of the other ones. But just so you know what these are, point slope form, let's say the point x1, y1 are, let's say that that is a point on the line.
And when someone puts this little subscript here, so if they just write an x, that means we're talking about a variable that can take on any value. If someone writes x with a subscript 1 and a y with a subscript 1, that's like saying a particular value x and a particular value of y, or a particular coordinate.
And you'll see that when we do the example. But point slope form says that, look, if I know a particular point, and if I know the slope of the line, then putting that line in point slope form would be y minus y1 is equal to m times x minus x1.
So, for example, and we'll do that in this video, if the point negative 3 comma 6 is on the line, then we'd say y minus 6 is equal to m times x minus negative 3, so it'll end up becoming x plus 3.
So this is a particular x, and a particular y. It could be a negative 3 and 6. So that's point slope form. Slope intercept form is y is equal to mx plus b, where once again m is the slope, b is the y-intercept-- where does the line intersect the y-axis-- what value does y take on when x is 0?
And then standard form is the form ax plus by is equal to c, where these are just two numbers, essentially. They really don't have any interpretation directly on the graph. So let's do this, let's figure out all of these forms.
So the first thing we want to do is figure out the slope. Once we figure out the slope, then point slope form is actually very, very, very straightforward to calculate. So, just to remind ourselves, slope, which is equal to m, which is going to be equal to the change in y over the change in x.
Now what is the change in y? If we view this as our end point, if we imagine that we are going from here to that point, what is the change in y?
Well, we have our end point, which is 0, y ends up at the 0, and y was at 6. So, our finishing y point is 0, our starting y point is 6. What was our finishing x point, or x-coordinate? Our finishing x-coordinate was 6. Let me make this very clear, I don't want to confuse you. So this 0, we have that 0, that is that 0 right there.
And then we have this 6, which was our starting y point, that is that 6 right there. And then we want our finishing x value-- that is that 6 right there, or that 6 right there-- and we want to subtract from that our starting x value.
Well, our starting x value is that right over there, that's that negative 3. And just to make sure we know what we're doing, this negative 3 is that negative 3, right there.
I'm just saying, if we go from that point to that point, our y went down by 6, right? We went from 6 to 0. Our y went down by 6. So we get 0 minus 6 is negative 6.Writing linear equations using the slope-intercept form Writing linear equations using the point-slope form and the standard form Parallel and perpendicular lines.
How to Write the Equation into Standard Form When Given the Slope and a Point on the Line Write the equation into y = mx + b using y - k = m (x - h).
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EXAMPLE 2 Rewrite each equation in Standard Form. EXAMPLE 1 Write an equation in Slope-Intercept form given the slope and a point on the line. a. m = –4 and passes through (–1, 3) EXAMPLE 1 Write an equation in point-slope form of the line that passes through the given point and has the given slope.
The equation of the straight line when one of the coordinate points are known can be represented as y - y1 = m(x - x1). These type of forms are known as point slope form. Equation of the straight line can also be calculated without the slope when two points (x1, y1) and (x2, y2) are given.
A line passes through the points negative 3, 6 and 6, 0. Find the equation of this line in point slope form, slope intercept form, standard form.
And the way to think about these, these are just three different ways of writing the same equation. So if you give me one of them, we can manipulate it to.
Image Source: Google Images. Babies usually follow a straight line of increasing body length as they start growing. This baby was born 20 inches long (y-intercept), and has been growing at .