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# How do I find a equation in a graph? Could anyone explain?

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Write an equation for the graph shown in the form y=ax+b.

I know I have to use the y=mx+b equation but I don't know how Oct 30, 2022

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m is the slope of the line.  That's the distance it goes vertically divided by the distance it goes horizontally.

In this case, using known points, the vertical distance is        (+2) – (0)   =   +2

In this case, using known points, the horizontal distance is    (+5) – (–5)  =  +10

So the slope, which is conventionally called "m" is 0.2

b is the y-intercept of the line.  That the point where the line crosses the y-axis.

Looking at the graph, it appears that the y-intercept is at (0,1)

So the y-intercept, which is conventionally called "b" is 1.

Plugging the values into y = mx + b, we find the equation to be  y = 0.2x + 1   tentatively

Sometimes it isn't as straightforward, so plug in those two known values of x to see if it works.

When x = –5,  does y = 0.2x + 1 equal 0 ?     (0.2 • –5) + 1  =  (–1) + (+1)  =  0  so yes

When x = +5,  does y = 0.2x + 1 equal 2 ?     (0.2 • +5) + 1  =  (+1) + (+1)  =  2  so yes

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Oct 30, 2022
#2
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So how could I do it if I was given a equation to graph?

or when its asking write a equation that intersects with this point?

Oct 30, 2022