SOLUTION: i need help but its writing equations parallel or perpendicular to a line. give the standard form of the equation of the line that is perpendicular to 4x+8y=1 and contains (-5

Algebra ->  Linear-equations -> SOLUTION: i need help but its writing equations parallel or perpendicular to a line. give the standard form of the equation of the line that is perpendicular to 4x+8y=1 and contains (-5      Log On


   

Question 583259: i need help but its writing equations parallel or perpendicular to a line.

give the standard form of the equation of the line that is perpendicular to 4x+8y=1 and contains (-5,4)
Answer by computergeek008(7) About Me  (Show Source):
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Give the standard form of the equation of the line that is perpendicular to 4x+8y=1 and contains (-5,4)
If a line is perpendicular to another line, that means it will have a negative reciprocal slope.
If we rearrange the equation of the given line into the slope-intercept form (y=mx+b), we can find the slope of the given line.
4x+8y = 1
8y = -4x+1
y+=+%28-1%2F2%29x+%2B+1%2F8
So the slope of the given line is -1%2F2. Since a line that is perpendicular to it will have a negative reciprocal slope, then that means the other line will have a slope of 2.
Now that we know the slope and a point on the line, use the point-slope formula y-y1+=+m%28x-x1%29 to find the equation:
y-4 = 2(x-(-5))
y-4 = 2x + 10
y = 2x + 14
or in standard form:
-2x+y = 14