James B. answered 05/04/17
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Find the equation of the line that passes through (-2, 5), and is perpendicular to the line ... 6x + y = 8
First, lints find the slope of the given line, by writing the equation in slope-intercept form ... y = mx + b
When written in this form, the slope of the line is "m".
6x + y = 8
Adding "-6x" to both sides of the equation, gives us
y = -6x + 8
Thus the slope of our line is "-6",
The slope of the line that is perpendicular to our line, has a slope that is the negative reciprocal of our line.
So if we take -6, change the sign, and take the reciprocal, we end up with a 1/6 ... the product of the slopes of lines that are perpendicular, is "-1" ... thus the slope of the perpendicular line is 1/6
We can now use the point-slope formula, because we have a point on the line, and we have the slope of the line.
y - y1 = m(x - x1)
y - 5 = (1/6)(x -(-2))
y - 5 = (1/6)(x + 2)
y - 5 = (1/6)(x) + (1/6)(2)
y - 5 = (1/6)x + 2/6
y - 5 = (1/6)x + 1/3
y = (1/6)x + 1/3 + 5
y = (1/6)x + 1/3 + 15/3
y = (1/6)x + 16/3
CHECK: when we plug the point (-2, 5) into the line, we should get a true statement
y = (1/6)x + 16/3
5 = (1/6)(-2) + 16/3
5 = -2/6 + 16/3
5 = -1/3 + 16/3
5 = 15/3
5 = 5
TRUE