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Write the equation of the line that passes throught the points (-1, 6) and (5, -4).

User Joaoprib
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1 Answer

18 votes
18 votes

Answer:

y = -5/3x + 13/3

Explanation:

(-1, 6) and (5, -4).

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:

(-4 - 6) / (5 - (-1))

Simplify the parentheses.

= (-10) / (5 + 1)

= (-10) / (6)

Simplify the fraction.

-10/6

= -5/3

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

y = -5/3x + 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 (5, -4). Plug in the x and y values into the x and y of the standard equation.

-4 = -5/3(5) + b

To find b, multiply the slope and the input of x(5).

-4 = -25/3 + b

Now, add 25/3 to both sides to isolate b.

-4 ⇒ -12/3

-12/3 + 25/3 = 13/3

13/3 = b

Plug this into your standard equation.

y = -5/3x + 13/3

This is your equation.

Check this by plugging in the other point you have not checked yet (-1, 6).

y = -5/3x + 13/3

6 = -5/3(-1) + 13/3

6 = 5/3 + 13/3

6 = 18/3

6 = 6

Your equation is correct.

Hope this helps!

User Michael Williams
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2.8k points