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La ecuación de la recta que pasa por los puntos (2,-1) y (1,-5) es:

y= 4x+9




y= 4x-9




y= x-9


ninguna de las anteriores

1 Answer

8 votes

Given:

A line passes through the points (2,-1) and (1,-5).

To find:

The equation of the line.

Solution:

If a line passes through the two points, then the equation of the line is


y-y_1=(y_2-y_1)/(x_2-x_1)(x-x_1)

The line passes through the points (2,-1) and (1,-5). So, the equation of the line is


y-(-1)=(-5-(-1))/(1-2)(x-2)


y+1=(-5+1)/(-1)(x-2)


y+1=(-4)/(-1)(x-2)


y+1=4(x-2)

Using distributive property, we get


y+1=4(x)+4(-2)


y+1=4x-8

Subtract 1 from both sides.


y+1-1=4x-8-1


y=4x-9

Therefore, the correct option is B.

User Min Khant Lu
by
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