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The points (2, 8) and (1, 2) fall on a particular line. What is its equation in slope-intercept form?

User AWB
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1 Answer

11 votes

Answer:

y = 6x - 4

Explanation:

(2, 8) & (1, 2)

First you want to find the slope of the line that passes through these points. To find the slope of the line, we use the slope formula: (y₂ - y₁) / (x₂ - x₁)

Plug in these values:

(2 - 8) / (1 - 2)

Simplify the parentheses.

= (-6) / (-1)

Simplify the fraction.

-6/-1

= 6

This is your slope. Plug this value into the standard slope-intercept equation of y = mx + b.

y = 6x + b

To find b, we want to plug in a value that we know is on this line: in this case, I will use the second point (1, 2). Plug in the x and y values into the x and y of the standard equation.

2 = 6(1) + b

To find b, multiply the slope and the input of x(1)

2 = 6 + b

Now, subtract 6 from both sides to isolate b.

-4 = b

Plug this into your standard equation.

y = 6x - 4

This is your equation.

Check this by plugging in the other point you have not checked yet (2, 8).

y = 6x - 4

8 = 6(2) - 4

8 = 12 - 4

8 = 8

Your equation is correct.

Hope this helps!

User Rich Maes
by
7.8k points

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