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jrbrown2
- Master | Next Rank: 500 Posts
- Posts: 103
- Joined: Sun Jun 10, 2007 7:10 pm
- Location: Brooklyn, NY
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Line L contains the points (2,3) and (p,q). If q = 2, which of the following could be the equation of line m, which is perpendicular to line L?
(A) 2x + y = px + 7
(B) 2x + y = –px
(C) x + 2y = px + 7
(D) y – 7 = x ÷ (p – 2)
(E) 2x + y = 7 – px
To start I figured out the slope of line L
Slope = (q-3)/(p-2) = (2-3)/(p-2) = -1/(p-2)
If line M is perpendicular to the line L then M's slope is the negative inverse of line L's slope.
So Slope of line M = (p-2)
The equation of a line is y = mx+b where m is the slope and b is the y intercept. I rewrote all of the answer choices in this form and selected the answer that had the correct slope of (p-2), which is the negative inverse of line L's slope.
(A) 2x + y = px + 7 Therefore Y = (p-2)x +7
(B) 2x + y = –px Therefore Y = (-p-2)x
(C) x + 2y = px + 7 Therefore Y = (p-1)x/2 + 7/2
(D) y – 7 = x ÷ (p – 2) Therefore Y = x/(p-2) + 7
(E) 2x + y = 7 – px Therefore Y = (-p-2)x +7
Choice A is the only choice that has (p-2) as its slope so A is the answer
(A) 2x + y = px + 7
(B) 2x + y = –px
(C) x + 2y = px + 7
(D) y – 7 = x ÷ (p – 2)
(E) 2x + y = 7 – px
To start I figured out the slope of line L
Slope = (q-3)/(p-2) = (2-3)/(p-2) = -1/(p-2)
If line M is perpendicular to the line L then M's slope is the negative inverse of line L's slope.
So Slope of line M = (p-2)
The equation of a line is y = mx+b where m is the slope and b is the y intercept. I rewrote all of the answer choices in this form and selected the answer that had the correct slope of (p-2), which is the negative inverse of line L's slope.
(A) 2x + y = px + 7 Therefore Y = (p-2)x +7
(B) 2x + y = –px Therefore Y = (-p-2)x
(C) x + 2y = px + 7 Therefore Y = (p-1)x/2 + 7/2
(D) y – 7 = x ÷ (p – 2) Therefore Y = x/(p-2) + 7
(E) 2x + y = 7 – px Therefore Y = (-p-2)x +7
Choice A is the only choice that has (p-2) as its slope so A is the answer
