Question

Y=3x-7 how do i graph it using form y=mx

Answer 1

start at the y-intercept, plot some points using the slope, then connect them using a straight line.

Explanation:

Slope-Intercept Form

Generally you'll have an equation in slope-intercept form, which is denoted as:
`y=mx+b`

This is a really useful form for a couple of reasons, and it has two key features. Firstly, the "m" represents the slope of the linear equation.

This makes sense the definition of slope is:
`\frac{\text{change in y}}{\text{change in x}}`

and we can generally define the points:

`\text{at x = 1, y = }m(1)+b\implies m+b\\\text{at x = 2, y = } m(2)+b\implies m + m + b\\\text{at x = 3, y = }m(3) + b\implies m + m + m +b\\\text{and so on...}`

as the x value increases by 1, the change in y is the "m" value, we have one more "m" than the previous x-value, so the slope is the "m" value, which is the coefficient of the x variable.

The second key feature of slope-intercept form is the y-intercept, which is represented as "b" in this form. This also makes sense because the y-intercept is simply when the x-value is zero, and if you plug in x=0 into the equation, you're only left with the "b" value

Graphing the Equation

Knowing these two things we can analyze the equation given:

`y = 3x-7`

since it's given in slope-intercept form, we know that slope = 3, and y-intercept = -7. We immediately know one point, which is the y-intercept, since the x-value is going to be zero at the y-intercept, so one point on the graph is: (0, -7)

now from this point we can draw the graph by going to the right one, and up three, by definition of a slope (as x increases by 1, the y-value increases by 3).

We can do something similar on the left side, except instead of right one and up three, we go left one, and down three. You may be asking why down three? Well as you go right one, you go up three, this means if you compare the previous point to the new point, the previous point is down three compared to the new point (which is to the right one), so if you were to go back, you would be going left one and down three.

Now from these points you can do the same thing to extend the line a bit, and since it's a linear equation you can connect them using a straight line.

I also attached a graph from desmos to illustrate what I was saying a bit and also show the graph.

Answer 2

Answer: See attached.

Explanation:

This slope-intercept form equation shows us that there is a y-intercept of -7. This means that (0, -7) will be a point on the line. Next, we have a slope of positive 3. This means we will count up three units, right one unit, plot a point. Then we repeat.