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Find the equation of the line that id perpendicular to -2x-9y=1 and passes through the point (-7,-5)

User Lovespeed
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1 Answer

1 vote

Answer:

y = (9/2)x + 26.5

Explanation:

Lets rewrote the equation in standard format of y = mx + b, where m is the slope and b is the y-intercept.

-2x-9y = 1

-9y = 2x + 1

y = -(2/9)x - (1/9)

The slope of this line is -(2/9)

A line that is perpendicular to this line will have a slope that is the negative inverse of -(2/9). That would be (9/2). So a perpendicular line will have the form of y = (9/2)x + b. Any value of b can be chosen and the lines will still be perpendicular to each other. However, we want to find a value of b that will force the line through point (-7,-5). This is done by using the point in the above equation and solving for b:

y = (9/2)x + b

-5 = (9/2)(-7) + b for point (-7,-5)

-5 = -(63/2) + b

b = -5 + (63/2)

b = -5 + 31.5

b = 26.5

The equation is y = (9/2)x + 26.5

See the attached graph.

Find the equation of the line that id perpendicular to -2x-9y=1 and passes through-example-1
User Bertrandg
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7.5k points