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What is an equation of the line that passes through the points (1, -7) and (-1, 5)?l

User Jeemin
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1 Answer

4 votes

Explanation:

since we have only points as information, let's us the point-slope form as equation :

y - y1 = a(x - x1)

a being the slope, (x1, y1) is a point on the line.

the slope is the ratio (y coordinate difference / x coordinate difference) when going from one point on the line to another. the direction itself does not matter, but is is important to use for the x and y difference calculations the same direction.

from (1, -7) to (-1, 5) we see

x changes by -2 (from 1 to -1).

y changes by +12 (from -7 to 5).

the slope is

+12/-2 = -6

so, when using e.g. (1, -7), our equation is

y - -7 = -6(x - 1)

y + 7 = -6x + 6

we could transform this now easily into the point-intercept form

y = ax + b

y + 7 = -6x + 6

y = -6x - 1

so, pick the form of equation that you like.

User Mdundas
by
8.0k points

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